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ADAPTeR is a prospective, phase II study of nivolumab (anti-PD-1) in 15 treatment-naive patients (115 multiregion tumor samples) with metastatic clear cell renal cell carcinoma (ccRCC) aiming to understand the mechanism underpinning therapeutic response. Genomic analyses show no correlation between tumor molecular features and response, whereas ccRCC-specific human endogenous retrovirus expression indirectly correlates with clinical response. T cell receptor (TCR) analysis reveals a significantly higher number of expanded TCR clones pre-treatment in responders suggesting pre-existing immunity. Maintenance of highly similar clusters of TCRs post-treatment predict response, suggesting ongoing antigen engagement and survival of families of T cells likely recognizing the same antigens. In responders, nivolumab-bound CD8+ T cells are expanded and express GZMK/B. Our data suggest nivolumab drives both maintenance and replacement of previously expanded T cell clones, but only maintenance correlates with response. We hypothesize that maintenance and boosting of a pre-existing response is a key element of anti-PD-1 mode of action.

While the genetic evolutionary features of solid tumour growth are becoming increasingly described, the spatial and physical nature of subclonal growth remains unclear. Here we utilise 102 macroscopic whole tumour images from clear cell renal cell carcinoma (ccRCC) patients, with matched genetic and phenotypic data from 756 biopsies. Utilising a digital image processing pipeline the boundaries between tumour and normal tissue were marked by a renal pathologist, and positions of boundary line and biopsy regions were extracted to X- and Y-coordinates. The coordinates were then integrated with genomic data to map exact spatial subclone locations, revealing how genetically distinct subclones grow and evolve spatially. A phenotype of advanced and more aggressive subclonal growth was present in the tumour centre, characterised by an elevated burden of somatic copy number alterations, higher necrosis, proliferation rate and Fuhrman grade. Moreover, metastasising subclones were found to preferentially originate from the tumour centre. Collectively these observations suggest a model of accelerated evolution in the tumour interior, with harsh hypoxic environmental conditions leading to heightened cellular turnover and greater opportunity for driver SCNAs to arise and expand due to selective advantage. Tumour subclone growth was found to be predominantly spatially contiguous in nature, with subclone dispersal a rare event found in two cases, which notably was associated with metastasis. In terms of genetic events, the largest subclones spatially were dominated by driver somatic copy number alterations, suggesting a large selective advantage can be conferred to subclones upon acquisition of these alterations. In conclusion, spatial dynamics is strongly associated with genomic alterations and plays an important role in tumour evolution.

International audience; Although thousands of solid tumors have been sequenced to date, a fundamental under-sampling bias isinherent in current methodologies. This is caused by a tissue sample input of fixed dimensions (e.g., 6 mmbiopsy), which becomes grossly under-powered as tumor volume scales. Here, we demonstrate representative sequencing (Rep-Seq) as a new method to achieve unbiased tumor tissue sampling. Rep-Seq uses fixed residual tumor material, which is homogenized and subjected to next-generation sequencing. Analysis of intratumor tumor mutation burden (TMB) variability shows a high level of misclassification using current single-biopsy methods, with 20% of lung and 52% of bladder tumors having at least one biopsy with high TMB butlow clonal TMB overall. Misclassification rates by contrast are reduced to 2% (lung) and 4% (bladder) when a more representative sampling methodology is used. Rep-Seq offers an improved sampling protocol for tumor profiling, with significant potential for improved clinical utility and more accurate deconvolution of clonal structure.

Tumor cells proliferate rapidly and thus are frequently subjected to replication stress and the risk of incomplete duplication of the genome. Fragile sites are replicated late, making them more vulnerable to damage when DNA replication fails to complete. Therefore, genomic alterations at fragile sites are commonly observed in tumors. FRA16D is one of the most common fragile sites in lung cancer, however, the nature of the tumor suppressor genes affected by FRA16D alterations has been controversial. Here, we show that the ATMIN gene, which encodes a cofactor required for activation of ATM kinase by replication stress, is located close to FRA16D and is commonly lost in lung adenocarcinoma. Low ATMIN expression was frequently observed in human lung adenocarcinoma tumors and was associated with reduced patient survival, suggesting that ATMIN functions as a tumor suppressor in lung adenocarcinoma. Heterozygous Atmin deletion significantly increased tumor cell proliferation, tumor burden, and tumor grade in the LSL-KRasG12D; Trp53 F/F (KP) mouse model of lung adenocarcinoma, identifying ATMIN as a haploinsufficient tumor suppressor. ATMIN-deficient KP lung tumor cells showed increased survival in response to replication stress and consequently accumulated DNA damage. Thus, our data identify ATMIN as a key gene affected by genomic deletions at FRA16D in lung adenocarcinoma. Significance: These findings identify ATMIN as a tumor suppressor in LUAD; fragility at chr16q23 correlates with loss of ATMIN in human LUAD and deletion of Atmin increases tumor burden in a LUAD mouse model.

The mammary gland is composed of a complex cellular hierarchy with unusual postnatal plasticity. The identities of stem/progenitor cell populations, as well as tumour-initiating cells that give rise to breast cancer, are incompletely understood. Here we show that Lgr6 marks rare populations of cells in both basal and luminal mammary gland compartments in mice. Lineage tracing analysis showed that Lgr6+ cells are unipotent progenitors, which expand clonally during puberty but diminish in adulthood. In pregnancy or following stimulation with ovarian hormones, adult Lgr6+ cells regained proliferative potency and their progeny formed alveoli over repeated pregnancies. Oncogenic mutations in Lgr6+ cells resulted in expansion of luminal cells, culminating in mammary gland tumours. Conversely, depletion of Lgr6+ cells in the MMTV-PyMT model of mammary tumorigenesis significantly impaired tumour growth. Thus, Lgr6 marks mammary gland progenitor cells that can initiate tumours, and cells of luminal breast tumours required for efficient tumour maintenance.

This study was supported by Cancer Research UK, AstraZeneca and Pfizer UK. Introduction: Phase I of the Cancer Research UK Stratified Medicine Programme (SMP1) was designed to roll out molecular pathology testing nationwide at the point of cancer diagnosis, as well as facilitate an infrastructure where surplus cancer tissue could be used for research. It offered a non-trial setting to examine common UK cancer genetics in a real-world context. Methods: A total of 26 sites in England, Wales and Scotland, recruited samples from 7814 patients for genetic examination between 2011 and 2013. Tumour types involved were breast, colorectal, lung, prostate, ovarian cancer and malignant melanoma. Centralised molecular testing of surplus material from resections or biopsies of primary/metastatic tissue was performed, with samples examined for 3-5 genetic alterations deemed to be of key interest in site-specific cancers by the National Cancer Research Institute Clinical Study groups. Results: 10 754 patients (98% of those approached) consented to participate, from which 7814 tumour samples were genetically analysed. In total, 53% had at least one genetic aberration detected. From 1885 patients with lung cancer, KRAS mutation was noted to be highly prevalent in adenocarcinoma (37%). In breast cancer (1873 patients), there was a striking contrast in TP53 mutation incidence between patients with ductal cancer (27.3%) and lobular cancer (3.4%). Vast inter-tumour heterogeneity of colorectal cancer (1550 patients) was observed, including myriad double and triple combinations of genetic aberrations. Significant losses of important clinical information included smoking status in lung cancer and loss of distinction between low-grade and high-grade serous ovarian cancers. Conclusion: Nationwide molecular pathology testing in a non-trial setting is feasible. The experience with SMP1 has been used to inform ongoing CRUK flagship programmes such as the CRUK National Lung MATRIX trial and TRACERx. Publisher PDF

Squamous cell carcinoma (SCC) can progress to malignant metastatic cancer, including an aggressive subtype known as spindle cell carcinoma (spSCC). spSCC formation involves epithelial-to-mesenchymal transition (EMT), yet the molecular basis of this event remains unknown. The transcriptional co-activator YAP undergoes recurrent amplification in human SCC and overexpression of YAP drives SCC formation in mice. Here, we show that human spSCC tumours also feature strong nuclear localisation of YAP and overexpression of activated YAP (NLS-YAP-5SA) with Keratin-5 (K5-CreERt) is sufficient to induce rapid formation of both SCC and spSCC in mice. spSCC tumours arise at sites of epithelial scratch wounding, where tumour-initiating epithelial cells undergo EMT to generate spSCC. Expression of the EMT transcription factor ZEB1 arises upon wounding and is a defining characteristic of spSCC in mice and humans. Thus, the wound healing response synergises with YAP to drive metaplastic transformation of SCC to spSCC.

Summary RAS family GTPases contribute directly to the regulation of type I phosphoinositide 3-kinases (PI3Ks) via RAS-binding domains in the PI3K catalytic p110 subunits. Disruption of this domain of p110α impairs RAS-mutant-oncogene-driven tumor formation and maintenance. Here, we test the effect of blocking the interaction of RAS with p110α on epidermal growth factor receptor (EGFR)-mutant-driven lung tumorigenesis. Disrupting the RAS-PI3K interaction inhibits activation of both AKT and RAC1 in EGFR-mutant lung cancer cells, leading to reduced growth and survival, and inhibits EGFR-mutant-induced tumor onset and promotes major regression of established tumors in an autochthonous mouse model of EGFR-mutant-induced lung adenocarcinoma. The RAS-PI3K interaction is thus an important signaling node and potential therapeutic target in EGFR-mutant lung cancer, even though RAS oncogenes are not themselves mutated in this setting, suggesting different strategies for tackling tyrosine kinase inhibitor resistance in lung cancer., Graphical Abstract, Highlights • Disrupting the interaction of PI 3-kinase with RAS impairs EGF activation of AKT and RAC • Mice bred with RAS-binding-domain-defective PI 3-kinase and activated EGFR mutant • Abrogating RAS binding to PI 3-kinase blocks EGFR-induced lung tumor initiation • Blocking the RAS-PI 3-kinase interaction induces regression of EGFR-induced tumors, The interaction between RAS and PI 3-kinase is essential for RAS-mutant-induced carcinogenesis. Murillo et al. show that in EGFR-mutant-driven lung cancer, disruption of the interaction of PI 3-kinase with normal RAS proteins blocks tumor initiation and promotes regression of existing tumors, highlighting an unexpected vulnerability of EGFR-driven lung cancer.

Summary Clear cell renal cell carcinoma (ccRCC) is characterized by near-universal loss of the short arm of chromosome 3, deleting several tumor suppressor genes. We analyzed whole genomes from 95 biopsies across 33 patients with clear cell renal cell carcinoma. We find hotspots of point mutations in the 5′ UTR of TERT, targeting a MYC-MAX-MAD1 repressor associated with telomere lengthening. The most common structural abnormality generates simultaneous 3p loss and 5q gain (36% patients), typically through chromothripsis. This event occurs in childhood or adolescence, generally as the initiating event that precedes emergence of the tumor’s most recent common ancestor by years to decades. Similar genomic changes drive inherited ccRCC. Modeling differences in age incidence between inherited and sporadic cancers suggests that the number of cells with 3p loss capable of initiating sporadic tumors is no more than a few hundred. Early development of ccRCC follows well-defined evolutionary trajectories, offering opportunity for early intervention., Graphical Abstract, Highlights • Novel hotspot of driver mutations in 5′-UTR repressor of TERT, expanding telomeres • Most common cause of 3p loss is a chromothripsis event, generating concurrent 5q gain • t(3;5) event occurs in childhood or adolescence, decades before tumor diagnosed • Initial clonal expansion after 3p loss starts from only a few hundred cells, Combination of whole-genome sequencing analysis and a multi-region sampling approach provides insights into the nature and timing of key oncogenic events in clear cell renal cell carcinoma, depicts the evolutionary trajectories of tumors in patients and highlights the opportunity for early intervention.

The evolutionary features of clear-cell renal cell carcinoma (ccRCC) have not been systematically studied to date. We analyzed 1,206 primary tumor regions from 101 patients recruited into the multi-center prospective study, TRACERx Renal. We observe up to 30 driver events per tumor and show that subclonal diversification is associated with known prognostic parameters. By resolving the patterns of driver event ordering, co-occurrence, and mutual exclusivity at clone level, we show the deterministic nature of clonal evolution. ccRCC can be grouped into seven evolutionary subtypes, ranging from tumors characterized by early fixation of multiple mutational and copy number drivers and rapid metastases to highly branched tumors with > 10 subclonal drivers and extensive parallel evolution associated with attenuated progression. We identify genetic diversity and chromosomal complexity as determinants of patient outcome. Our insights reconcile the variable clinical behavior of ccRCC and suggest evolutionary potential as a biomarker for both intervention and surveillance. We thank Aida Murra, Naheed Shaikh, Justine Korteweg, Jeremy Tai, Eleanor Carlyle, Leonora Conneely, KimEdmonds, Karla Lingard, Karen O'Meara, Helen Breeze, Sarah Sarker, Lesley Cooper, Linda Shephard, Susie Slater, and Catherine Rogers for study support. We thank the patients and their families. S.T. and H.X. are funded by Cancer Research UK (CRUK) (C50947/A18176). S.T., T.C., J.L., and M.G. are funded by the National Institute for Health Research (NIHR) Biomedical Research Centre (BRC) at the Royal Marsden Hospital and Institute of Cancer Research (A109). J.I.L. is funded by the Ministerio de Economia y Competitividad (MINECO, SAF2016-79847-R). M.S., A.S., J. Lynch, R.F., L.A., and L.S. are funded by the Royal Marsden Cancer Charity. K.L. is funded by UK Medical Research Council (MR/P014712/1). T.B.K.W. is funded by the European Union Seventh Framework Programme (FP7-People-2013-ITN). M.J.-H. is funded by the NIHR. N.M.L. is a Winton Group Leader in recognition of the Winton Charitable Foundation's support towards the establishment of The Francis Crick Institute. N.M.L. is additionally funded by a Wellcome Trust Joint Investigator Award (103760/Z/14/Z) and the MRC eMedLab Medical Bioinformatics Infrastructure Award (MR/L016311/1). M.K. is funded by the Danish Cancer Society grant (R90-A6213). P.C. is funded by the Wellcome Trust (WT088340MA). N.M. receives funding from CRUK, Rosetrees, and the NIHR BRC at University College London Hospitals. C.S. is a Royal Society Napier Research Professor. C.S. is funded by Cancer Research UK (TRACERx and CRUK Cancer Immunotherapy Catalyst Network), the CRUK Lung Cancer Centre of Excellence, Stand Up 2 Cancer (SU2C), the Rosetrees and Stoneygate Trusts, NovoNordisk Foundation (THESEUS), Marie Curie Network PloidyNet, the NIHR BRC at University College London Hospitals, and the CRUK University College London Experimental Cancer Medicine Centre. C.S., O.P., D.R., I.C., and Z.S. are funded by NovoNordisk Foundation (16584). O.P., D.R., and I.C. are funded by the National Research, Development and Innovation Office of Hungary (NVKP_16-1-20160004). This work was supported by CRUK (Clinical Scientist Fellowship to S.T., C50947/A18176), The Francis Crick Institute, which receives its core funding from Cancer Reseach UK (FC010110), the UK Medical Research Council (FC010110), the Wellcome Trust (FC010110), and NIHR BRC at the Royal Marsden Hospital and Institute of Cancer Research (A109). High-performance computing was supported by eMedLab. The results published here are in whole or part based upon data generated by the TCGA Research Network: http://cancergenome.nih.gov/.

Highlights • Symptomatic gastric exophytic GIST diagnosed by computerized tomography. • Pathology of resected specimen revealed segmental diffuse hyperplasia of the Cajal Cells with multifocal GISTs. • Similarity to familiar GIST syndromes, excluded by detection of a somatic c-KIT mutation in exon 11 and inexistence of clinical features of NF-1., Introduction Gastrointestinal stromal tumours (GISTs) are thought to derive from or differentiate towards the interstitial cells of Cajal (ICC) as most demonstrate a similar immunoprofile: CD117+, CD34+ and DOG1+. ICC hyperplasia refers to KIT-expressing microscopic spindle cell proliferations involving the myenteric plexus. Case report 74 year-old male presented with a 5-year history of heartburn and dysphagia. Imaging revealed a 4 cm GIST in the gastric fundus. Pathology of the resected specimen revealed diffuse segmental ICC hyperplasia harbouring two macroscopic GISTs and a ‘tumorlet’. A mutation in c-KIT exon 11 was detected in both the solid and the diffuse components. Discussion ICC hyperplasia can occur either as a sporadic focal lesion or in a syndromic setting, known to predispose to multiple GIST tumours at different sites. The majority of cases of sporadic ICC hyperplasia previously reported were of localised type. The hereditary form is mostly caused by germline mutations in c-KIT and PDGFRA or in patients with NF-1 andpresents as a diffuse hyperplasia, usually with a confluent, nodular or multifocal growth pattern. Conclusion We describe a diffuse form of sporadic ICC hyperplasia harbouring multifocal GISTs, mimicking diffuse ICC hyperplasia in hereditary GIST syndromes. Detection of somatic c-KIT exon 11 mutation ruled out a hereditary disorder.

Metabolic reprogramming in cancer enhances macromolecule biosynthesis and supports cell survival. Oncogenic drivers affect metabolism by altering distinct metabolic processes and render cancer cells sensitive to perturbations of the metabolic network. This study aimed to identify selective metabolic dependencies in breast cancer by investigating 17 breast cancer cells lines representative of the genetic diversity of the disease. Using a functional screen, we demonstrate here that monocarboxylate transporter 4 (MCT4) is an important regulator of breast cancer cell survival. MCT4 supports pH maintenance, lactate secretion and non-oxidative glucose metabolism in breast cancer cells. Moreover, MCT4 depletion caused an increased dependence of cancer cells on mitochondrial respiration and glutamine metabolism. MCT4 depletion reduced the ability of breast cancer cells to grow in a three-dimensional (3D) matrix or as multilayered spheroids. Moreover, MCT4 expression is regulated by the PI3K-Akt signalling pathway and highly expressed in HER2-positive breast cancers. These results suggest that MCT4 is a potential therapeutic target in defined breast cancer subtypes and reveal novel avenues for combination treatment.

Molecular tumor profiling for patients with advanced or recurrent solid tumors is increasingly adopted as standard of care in oncology, as it has been demonstrated that improved clinical outcomes can result from selection of the optimal therapy for individual patients. The Clinical Utility of a molecular profiling approach must demonstrate whether they lead to a reconsideration of the treatment plan and whether this improves the clinical outcome in profiled patients. Our comparison of 4 commercially available molecular profiling services and those of purely academic approaches, revealed a wide range of impact on treatment choice and clinical benefit. These variations in profiling service performance highlight the need for ongoing justification, quality control and evaluation if this methodology is to be effectively deployed within the clinical setting. It also means that a profiling approach without clinical outcome data can only be considered to perform in line with the lowest performing comparator in terms of clinical utility and cost effectiveness until otherwise demonstrated.

Summary Chromosomal instability (CIN) contributes to cancer evolution, intratumor heterogeneity, and drug resistance. CIN is driven by chromosome segregation errors and a tolerance phenotype that permits the propagation of aneuploid genomes. Through genomic analysis of colorectal cancers and cell lines, we find frequent loss of heterozygosity and mutations in BCL9L in aneuploid tumors. BCL9L deficiency promoted tolerance of chromosome missegregation events, propagation of aneuploidy, and genetic heterogeneity in xenograft models likely through modulation of Wnt signaling. We find that BCL9L dysfunction contributes to aneuploidy tolerance in both TP53-WT and mutant cells by reducing basal caspase-2 levels and preventing cleavage of MDM2 and BID. Efforts to exploit aneuploidy tolerance mechanisms and the BCL9L/caspase-2/BID axis may limit cancer diversity and evolution., Graphical Abstract, Highlights • Loss-of-function alterations in BCL9L are frequent in aneuploid CRC • BCL9L dysfunction drives aneuploidy tolerance by reducing levels of caspase-2 • Caspase-2 activation following aneuploidy results in MDM2 and BID cleavage • p53 stabilization after chromosome missegregation is regulated by caspase-2, López-García et al. find that BCL9L is often genetically inactivated in human colorectal cancers with chromosomal instability. BCL9L dysfunction promotes aneuploidy tolerance by reducing basal caspase-2 levels and preventing cleavage of MDM2 and BID independent of TP53 mutation status.

Direct interaction of RAS with the P13K p110 alpha subunit mediates RAS-driven tumor development: however, it is not clear how p110 alpha/RAS-dependant signaling mediates interactions between tumors and host tissues. Here, using a murine tumor cell transfer model, we demonstrated that disruption of the interaction between RAS and p110 alpha within host tissue reduced tumor growth and tumor-induced angiogenesis, leading to improved survival of tumor-bearing mice, even when this interaction was intact in the transferred tumor. Furthermore, functional interaction of RAS with p110 alpha in host tissue was required for efficient establishment and growth of metastatic tumors. Inhibition of RAS and p110 alpha interaction prevented proper VEGF-A and FGF-2 signaling, which are required for efficient angiogenesis. Additionally, disruption of the RAS and p110 alpha interaction altered the nature of tumor-associated macrophages, inducing expression of markers typical for macrophage populations with reduced tumor-promoting capacity. Together, these results indicate that a functional RAS interaction with P13K p110 alpha, in host tissue is required for the establishment of a growth-permissive environment for the tumor, particularly for tumor-induced angiogenesis. Targeting the interaction of RAS with P13K has the potential to impair tumor formation by altering the tumorhost relationship, in addition to previously described tumor cell-autonomous effects.

Ciliated foregut cysts are rare anomalies due to aberrant embryological development. Only a small number of gallbladder ciliated foregut cysts have been reported. We report the case of a 29-year-old woman presenting with epigastric pain associated with diarrhoea and vomiting, who was found to have raised serum bilirubin levels and abnormal liver function tests. Following a diagnostic pathway including abdominal ultrasound, magnetic resonance cholangiopancreatography and endoscopic ultrasound the gallbladder cyst was provisionally diagnosed to be a cyst arising from the cystic duct or a duplicated gallbladder. A laparoscopic cholecystectomy was carried out and histopathology identified a ciliated foregut gallbladder cyst. The postoperative course was uneventful. In this report we offer what we believe to be an optimal diagnostic pathway and therapeutic strategy for this rare congenital cyst.

We used a combination of whole-genome sequencing and in vitro validation to show that mutations that activated at least two pro-growth/survival pathways mediated intrinsic resistance to BRAF inhibition in a melanoma patient. These data demonstrate how in-depth analysis can reveal intrinsic resistance to standard of care, providing an opportunity for alternative therapeutic strategies for patients who are likely to fail first-line treat-575 ment., Background BRAF is mutated in ∼42% of human melanomas (COSMIC. http://www.sanger.ac.uk/genetics/CGP/cosmic/) and pharmacological BRAF inhibitors such as vemurafenib and dabrafenib achieve dramatic responses in patients whose tumours harbour BRAFV600 mutations. Objective responses occur in ∼50% of patients and disease stabilisation in a further ∼30%, but ∼20% of patients present primary or innate resistance and do not respond. Here, we investigated the underlying cause of treatment failure in a patient with BRAF mutant melanoma who presented primary resistance. Methods We carried out whole-genome sequencing and single nucleotide polymorphism (SNP) array analysis of five metastatic tumours from the patient. We validated mechanisms of resistance in a cell line derived from the patient's tumour. Results We observed that the majority of the single-nucleotide variants identified were shared across all tumour sites, but also saw site-specific copy-number alterations in discrete cell populations at different sites. We found that two ubiquitous mutations mediated resistance to BRAF inhibition in these tumours. A mutation in GNAQ sustained mitogen-activated protein kinase (MAPK) signalling, whereas a mutation in PTEN activated the PI3 K/AKT pathway. Inhibition of both pathways synergised to block the growth of the cells. Conclusions Our analyses show that the five metastases arose from a common progenitor and acquired additional alterations after disease dissemination. We demonstrate that a distinct combination of mutations mediated primary resistance to BRAF inhibition in this patient. These mutations were present in all five tumours and in a tumour sample taken before BRAF inhibitor treatment was administered. Inhibition of both pathways was required to block tumour cell growth, suggesting that combined targeting of these pathways could have been a valid therapeutic approach for this patient.

Summary RAC1 P29 is the third most commonly mutated codon in human cutaneous melanoma, after BRAF V600 and NRAS Q61. Here, we study the role of RAC1P29S in melanoma development and reveal that RAC1P29S activates PAK, AKT, and a gene expression program initiated by the SRF/MRTF transcriptional pathway, which results in a melanocytic to mesenchymal phenotypic switch. Mice with ubiquitous expression of RAC1P29S from the endogenous locus develop lymphoma. When expressed only in melanocytes, RAC1P29S cooperates with oncogenic BRAF or with NF1-loss to promote tumorigenesis. RAC1P29S also drives resistance to BRAF inhibitors, which is reversed by SRF/MRTF inhibitors. These findings establish RAC1P29S as a promoter of melanoma initiation and mediator of therapy resistance, while identifying SRF/MRTF as a potential therapeutic target., Graphical Abstract, Highlights • RAC1P29S activates PAK, AKT, and the SRF/MRTF transcription program in melanocytes • RAC1P29S induces a melanocytic to mesenchymal transition through SRF/MRTF and PAK • RAC1P29S cooperates with BRAF mutation or NF1 deletion to promote melanomagenesis • RAC1P29S induces resistance to BRAF inhibitors through SRF/MRTF, RAC1P29S is a common mutation in human cutaneous melanoma. Lionarons et al. show that RAC1P29S induces a melanocytic to mesenchymal switch via an SRF/MRTF-mediated gene expression program, cooperates with BRAF in melanomagenesis, and drives BRAF inhibitor resistance, which is reversed by SRF/MRTF inhibition.

Summary RAS proteins directly activate PI3-kinases. Mice bearing a germline mutation in the RAS binding domain of the p110α subunit of PI3-kinse are resistant to the development of RAS-driven tumors. However, it is unknown whether interaction of RAS with PI3-kinase is required in established tumors. The need for RAS interaction with p110α in the maintenance of mutant Kras-driven lung tumors was explored using an inducible mouse model. In established tumors, removal of the ability of p110α to interact with RAS causes long-term tumor stasis and partial regression. This is a tumor cell-autonomous effect, which is improved significantly by combination with MEK inhibition. Total removal of p110α expression or activity has comparable effects, albeit with greater toxicities., Highlights • Inducible disruption of PI3-kinase p110α interaction with RAS was modeled in mice • Blocking RAS/p110α interaction in established lung tumors causes partial regression • Blocking RAS/p110α binding has effects similar to p110α deletion on tumor regression • Coordinate MEK inhibition is required for major regression of Kras mutant lung cancer

The incidence of oesophagogastric junctional (OGJ) adenocarcinoma is rising rapidly in western countries, in contrast to the declining frequency of distal gastric carcinoma. Treatment options for adenocarcinomas involving the oesophagogastric junction are limited and the overall prognosis is extremely poor. To determine the genomic landscape of OGJ adenocarcinoma, exomes of eight tumours and matched germline DNA were subjected to massively parallel DNA sequencing. Microsatellite instability was observed in three tumours which coincided with an elevated number of somatic mutations. In total, 117 genes were identified that had predicted coding alterations in more than one tumour. Potentially actionable coding mutations were identified in 67 of these genes, including those in CR2, HGF , FGFR4, and ESRRB. Twenty-nine genes harbouring somatic coding mutations and copy number changes in the MSS OGJ dataset are also known to be altered with similar predicted functional consequence in other tumour types. Compared with the published mutational profile of gastric cancers, 49% (57/117) of recurrently mutated genes were unique to OGJ tumours. TP53, SYNE1, and ARID1A were amongst the most frequently mutated genes in a larger OGJ cohort. Our study provides an insight into the mutational landscape of OGJ adenocarcinomas and confirms that this is a highly mutated and heterogeneous disease. Furthermore, we have uncovered somatic mutations in therapeutically relevant genes which may represent candidate drug targets.

Background Phase I trials of the microtubule stabilising agent patupilone showed encouraging tumour control and response rates in patients with metastatic colorectal cancer. Methods Patients with metastatic or locally recurrent colorectal cancer who had progressed following treatment with oxaliplatin, irinotecan and fluoropyrimidines were treated with patupilone (8 mg/m2 IV every 3 weeks) in combination with dexamethasone or prednisolone. Results The trial was closed early after 29 patients had been enrolled due to concerns about toxicity. 20 patients (71.4 %) experienced at least one grade 3–5 toxicity, most commonly diarrhoea (14 patients), dehydration (7 patients) and lethargy (6 patients). The 12 week progression-free survival rate was 16.7 % (95 % CI 6.1 %–36.5 %) in the 24 patients with a 12 week scan available or who had died prior to the 12 week scan. No complete or partial responses were seen by 12 weeks. The median progression-free survival was 2.6 months (95 % CI 2.3–2.9) and median overall survival was 6.1 months (95 % CI 3.7–8.4). Conclusion Patupilone given at a dose of 8 mg/m2 IV over 20 min every 3 weeks was associated with high levels of toxicity and no significant evidence of efficacy in patients with pre-treated colorectal cancer.

Mucosal melanoma displays distinct clinical and epidemiological features compared to cutaneous melanoma. Here we used whole genome and whole exome sequencing to characterize the somatic alterations and mutation spectra in the genomes of ten mucosal melanomas. We observed somatic mutation rates that are considerably lower than occur in sun-exposed cutaneous melanoma, but comparable to the rates seen in cancers not associated with exposure to known mutagens. In particular, the mutation signatures are not indicative of ultraviolet light- or tobacco smoke-induced DNA damage. Genes previously reported as mutated in other cancers were also mutated in mucosal melanoma. Notably, there were substantially more copy number and structural variations in mucosal melanoma than have been reported in cutaneous melanoma. Thus, mucosal and cutaneous melanomas are distinct diseases with discrete genetic features. Our data suggest that different mechanisms underlie the genesis of these diseases and that structural variations play a more important role in mucosal than in cutaneous melanomagenesis.

BACKGROUND & AIMS: Pancreatitis is the most important risk factor for pancreatic ductal adenocarcinoma (PDAC). Pancreatitis predisposes to PDAC because it induces a process of acinar cell reprogramming known as acinar-to-ductal metaplasia (ADM)-a precursor of pancreatic intraepithelial neoplasia lesions that can progress to PDAC. Mutations in KRAS are found at the earliest stages of pancreatic tumorigenesis, and it appears to be a gatekeeper to cancer progression. We investigated how mutations in KRAS cooperate with pancreatitis to promote pancreatic cancer progression in mice.METHODS: We generated mice carrying conditional alleles of Yap1 and Taz and disrupted Yap1 and Taz using a Cre-lox recombination strategy in adult mouse pancreatic acinar cells (Yap1fl/fl;Tazfl/fl;Ela1-CreERT2). We crossed these mice with LSL-KrasG12D mice, which express a constitutively active form of KRAS after Cre recombination. Pancreatic tumor initiation and progression were analyzed after chemically induced pancreatitis. We analyzed pancreatic tissues from patients with pancreatitis or PDAC by immunohistochemistry.RESULTS: Oncogenic activation of KRAS in normal, untransformed acinar cells in the pancreatic tissues of mice resulted in increased levels of pancreatitis-induced ADM. Expression of the constitutive active form of KRAS in this system led to activation of the transcriptional regulators YAP1 and TAZ; their function was required for pancreatitis-induced ADM in mice. The JAK-STAT3 pathway was a downstream effector of KRAS signaling via YAP1 and TAZ. YAP1 and TAZ directly mediated transcriptional activation of several genes in the JAK-STAT3 signaling pathway; this could be a mechanism by which acinar cells that express activated KRAS become susceptible to inflammation.CONCLUSIONS: We identified a mechanism by which oncogenic KRAS facilitates ADM and thereby generates the cells that initiate neoplastic progression. This process involves activation of YAP1 and TAZ in acinar cells, which up-regulate JAK-STAT3 signaling to promote development of PDAC in mice.

Monoallelic APC and biallelic MYH (homolog of Escherichia coli mutY) germ-line mutations are independently associated with a strong predisposition to colorectal adenomas and carcinoma in humans. Whereas mice heterozygous for mutant Apc develop intestinal tumors, mice homozygous for mutant Myh do not show increased tumor susceptibility. We analyzed the phenotype of ApcMin/+/Myh−/− mice and found that they developed significantly more adenomas in the small intestine than did ApcMin/+/Myh+/+ or ApcMin/+/Myh+/− mice (median 231 versus 151 versus 152). In the large bowel, ApcMin/+/Myh−/− mice showed significant increases in the number of aberrant crypt foci. In addition, ApcMin/+/Myh−/− mice developed an increased number of mammary tumors. Molecular analyses suggested that at least 19% of intestinal tumors from ApcMin/+/Myh−/− mice had acquired intragenic Apc mutations rather than allelic loss. Consistent with a defect in base excision repair, three intragenic Apc mutations in polyps without allelic loss from ApcMin/+/Myh−/− mice were shown to be G:C to T:A transversions which resulted in termination codons; no such mutations were found in polyps from ApcMin/+/Myh+/+ or ApcMin/+/Myh+/− mice. Tumors from ApcMin/+/Myh+/− mice harbored neither somatic mutations nor allelic loss at Myh. Thus, homozygous, but not heterozygous, Myh deficiency enhanced intestinal tumorigenesis in ApcMin/+ mice. The excess small-bowel adenomas in ApcMin/+/Myh−/− mice, therefore, appear to be a model of MYH-associated polyposis in humans.

Background and aims Adenomatous polyposis coli ( APC ) is a tumour suppressor gene mutated in the germline of patients with familial adenomatous polyposis (FAP) and somatically in most colorectal cancers. APC mutations impair β-catenin degradation, resulting in increased Wnt signalling. The most frequent APC mutation is a codon 1309 truncation that is associated with severe FAP. A previous study compared two mouse models of intestinal tumorigenesis, Apc R850X (Min) and Apc 1322T (1322T), the latter a model of human codon 1309 changes. 1322T mice had more severe polyposis but, surprisingly, these tumours had lower levels of nuclear β-catenin than Min tumours. The consequences of these different β-catenin levels were investigated. Methods Enterocytes were isolated from 1322T and Min tumours by microdissection and gene expression profiling was performed. Differentially expressed Wnt targets and other stem cell markers were validated using quantitative PCR, in situ hybridisation and immunohistochemistry. Results As expected, lower nuclear β-catenin levels in 1322T lesions were associated with generally lower levels of Wnt target expression. However, expression of the Wnt target and stem cell marker Lgr5 was significantly higher in 1322T tumours than in Min tumours. Other stem cell markers (Musashi1, Bmi1 and the Wnt target Cd44) were also at higher levels in 1322T tumours. In addition, expression of the Bmp antagonist Gremlin1 was higher in 1322T tumours, together with lower Bmp2 and Bmp4 expression. Conclusions The severe phenotype caused by truncation of Apc at codon 1322 is associated with an increased number of stem cells. Thus, a submaximal level of Wnt signalling favours the stem cell phenotype and this may promote tumorigenesis. A level of Wnt signalling exists that is too high for optimal tumour growth.

Germline mutations in the fumarate hydratase (FH) tumor suppressor gene predispose to leiomyomatosis, renal cysts, and renal cell cancer (HLRCC). HLRCC tumors overexpress HIF1alpha and hypoxia pathway genes. We conditionally inactivated mouse Fh1 in the kidney. Fh1 mutants developed multiple clonal renal cysts that overexpressed Hif1alpha and Hif2alpha. Hif targets, such as Glut1 and Vegf, were upregulated. We found that Fh1-deficient murine embryonic stem cells and renal carcinomas from HLRCC showed similar overexpression of HIF and hypoxia pathway components to the mouse cysts. Our data have shown in vivo that pseudohypoxic drive, resulting from HIF1alpha (and HIF2alpha) overexpression, is a direct consequence of Fh1 inactivation. Our mouse may be useful for testing therapeutic interventions that target angiogenesis and HIF-prolyl hydroxylation.

Investigation of genetic changes in tumours by loss of heterozygosity (LOH) is a powerful technique for identifying chromosomal regions that may contain tumour suppressor genes. LOH has been described on chromosome 6 in ovarian carcinoma using restriction fragment length polymorphism analysis with a small number of probes. We studied 29 ovarian carcinomas with 19 probes mapping to chromosome 6. Sixteen of the 29 tumours showed LOH on 6q (55%). Of these 16, 63% showed loss of all informative markers on that arm. One tumour showed loss of 6q24-qter, localising the putative tumour suppressor gene to that region. Loss on 6p was 28% overall. However, using three dinucleotide repeat primer pairs from 6p to study LOH in seven selected tumours, LOH was demonstrated at both 6p22.3-pter and at 6p12-6p22. These results confirm that 6q harbours a tumour suppressor gene of relevance to ovarian carcinoma and suggest that there may also be a similar gene(s) on 6p. By Southern analysis, there was no evidence of genomic rearrangements of the oestrogen receptor gene, located at 6q25.1. LOH on 6q was more common in high than low grade tumours. The relevance of our findings to previous work in ovarian cancer and other solid tumours is discussed. Images Figure 1 Figure 3 Figure 4

Reciprocal interactions between malignant and stromal cells create a local microenvironment that fosters tumor growth. Extracellular vesicles (EVs) such as exosomes, microvesicles, and large oncosomes are involved in tumor–stroma communication by shuttling signaling cargo and other molecules. Here we discuss how EVs released by cancer or stromal cells impact the proliferation, differentiation, and metabolism of tumors.

Rho-associated kinases 1 and 2 (ROCK1/2) are Rho-GTPase effectors that control key aspects of the actin cytoskeleton, but their role in proliferation and cancer initiation or progression is not known. Here, we provide evidence that ROCK1 and ROCK2 act redundantly to maintain actomyosin contractility and cell proliferation and that their loss leads to cell-cycle arrest and cellular senescence. This phenotype arises from down-regulation of the essential cell-cycle proteins CyclinA, CKS1 and CDK1. Accordingly, while the loss of either Rock1 or Rock2 had no negative impact on tumorigenesis in mouse models of non-small cell lung cancer and melanoma, loss of both blocked tumor formation, as no tumors arise in which both Rock1 and Rock2 have been genetically deleted. Our results reveal an indispensable role for ROCK, yet redundant role for isoforms 1 and 2, in cell cycle progression and tumorigenesis, possibly through the maintenance of cellular contractility. DOI: http://dx.doi.org/10.7554/eLife.12203.001, eLife digest Animal cells contain a structure called the cytoskeleton, which helps give the cells their shape. This structure can rapidly disassemble and reassemble, which enables cells to change their shape, move and divide into two. Many proteins are involved in controlling these processes. In particular, two proteins called ROCK1 and ROCK2 are known to be important for helping cancer cells move. However, investigations into the exact roles of these proteins have so far produced contradictory results. Kümper et al. have now developed a more refined method of studying what ROCK1 and ROCK2 do in cells. This involves genetically engineering mice in a way that makes it possible to control whether ROCK1 and ROCK2 are produced in specific cell types and tissues. Studying cells that had been taken from these mice revealed that cells that lacked both proteins could not contract. Moreover, these cells became bigger and flattened out. This change in appearance went hand in hand with the cells becoming unable to divide and form new cells. However, cells that lacked just one type of ROCK protein were still able to divide and proliferate. As tumors form as a result of cells dividing and proliferating uncontrollably, Kümper et al. then studied how the ROCK proteins affect tumor development in mice that are susceptible to lung or skin cancer. Although cancerous cells were found that contained just one type of ROCK protein, no tumor cells were found that lacked both ROCK1 and ROCK2, further confirming that having one ROCK protein is essential for tumor formation. Overall, it appears that within the systems studied ROCK1 and ROCK2 perform the same roles, and that ROCK proteins are indispensable for cell proliferation and hence tumor development. The next challenge will be to identify the tumor types that are highly dependent on processes driven by the ROCK proteins. Further work could then investigate whether drugs that inhibit the activity of the ROCK proteins block the growth and spread of these tumors. DOI: http://dx.doi.org/10.7554/eLife.12203.002

SummaryNon-small cell lung cancer (NSCLC) is the most frequent cause of cancer deaths worldwide; nearly half contain mutations in the receptor tyrosine kinase/RAS pathway. Here we show that RAS-pathway mutant NSCLC cells depend on the transcription factor GATA2. Loss of GATA2 reduced the viability of NSCLC cells with RAS-pathway mutations, whereas wild-type cells were unaffected. Integrated gene expression and genome occupancy analyses revealed GATA2 regulation of the proteasome, and IL-1-signaling, and Rho-signaling pathways. These pathways were functionally significant, as reactivation rescued viability after GATA2 depletion. In a Kras-driven NSCLC mouse model, Gata2 loss dramatically reduced tumor development. Furthermore, Gata2 deletion in established Kras mutant tumors induced striking regression. Although GATA2 itself is likely undruggable, combined suppression of GATA2-regulated pathways with clinically approved inhibitors caused marked tumor clearance. Discovery of the nononcogene addiction of KRAS mutant lung cancers to GATA2 presents a network of druggable pathways for therapeutic exploitation.

Pancreatic ductal adenocarcinoma (PDAC) has an extremely poor prognosis. Median survival for metastatic patients is six to nine months and survivors beyond one year are exceptional. Pancreatic cancer is resistant to conventional chemotherapy and is often diagnosed at advanced stages. However, immunotherapy is a rapidly advancing new treatment modality, which shows promise in many solid tumor types.​ We present a patient with metastatic pancreatic cancer who underwent a synchronous resection of the primary tumour (pancreatoduodenectomy) and metastatic site (left hepatectomy) after multimodality neoadjuvant treatment with gemcitabine, nab-paclitaxel, and immunotherapy backbone with IMM-101 (an intradermally applied immunomodulator), as well as consolidation chemoradiation. Pathology of the specimens showed a complete response in both sites of the disease. The patient remains alive four years from the initial diagnosis and continues on maintenance immunotherapy. This exceptional response to initial chemo-immunotherapy was followed by a novel and off-protocol approach of low-dose capecitabine and IMM-101 as a maintenance strategy. The survival benefit and sustained performance status could set this as a new paradigm for the treatment of oligometastatic pancreatic cancer following response to systemic therapy and immunotherapy.​

Adenomatous polyposis coli (APC) mutations are found in most colorectal tumours. These mutations are almost always protein-truncating, deleting both central domains that regulate Wnt signalling and C-terminal domains that interact with the cytoskeleton. The importance of Wnt dysregulation for colorectal tumourigenesis is well characterized. It is, however, unclear whether loss of C-terminal functions contributes to tumourigenesis, although this protein region has been implicated in cellular processes—including polarity, migration, mitosis, and chromosomal instability (CIN)—that have been postulated as critical for the development and progression of intestinal tumours. Since almost all APC mutations in human patients disrupt both central and C-terminal regions, we created a mouse model to test the role of the C-terminus of APC in intestinal tumourigenesis. This mouse (Apc) carries an internal deletion within Apc that dysregulates Wnt by removing the beta-catenin-binding and SAMP repeats, but leaves the C-terminus intact. We compared Apc mice with Apc animals. The latter allele represented the most commonly found human APC mutation and was identical to Apc except for absence of the entire C-terminus. Apc mice developed numerous intestinal adenomas indistinguishable in number, location, and dysplasia from those seen in Apc mice. No carcinomas were found in Apc or Apc animals. While similar disruption of the Wnt signalling pathway was observed in tumours from both mice, no evidence of differential C-terminus functions (such as cell migration, CIN, or localization of APC and EB1) was seen. We conclude that the C-terminus of APC does not influence intestinal adenoma development or progression. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

BackgroundCholangiocarcinoma (CC) is a rare tumour with a dismal prognosis. As conventional medical management offers minimal survival benefit, surgery currently represents the only chance of cure. We evaluated DNA copy number (CN) alterations in CC to identify novel therapeutic targets.MethodsDNA was extracted from 32CC samples. Bacterial artificial chromosome (BAC) array comparative genomic hybridization was performed using microarray slides containing 3400 BAC clones covering the whole human genome at distances of 1Mb. Data were analysed within the R statistical environment.ResultsDNA CN gains (89 regions) occurred more frequently than DNA CN losses (55 regions). Six regions of gain were identified in all cases on chromosomes 16, 17, 19 and 22. Twenty regions were frequently gained on chromosomes 1, 5, 7, 9, 11, 12, 16, 17, 19, 20 and 21. The BAC clones covering ERBB2, MEK2 and PDGFB genes were gained in all cases. Regions covering MTOR, VEGFR 3, PDGFA, RAF1, VEGFA and EGFR genes were frequently gained.ConclusionsWe identified CN gains in the region of 11 useful molecular targets. Findings of variable gains in some regions in this and other studies support the argument for molecular stratification before treatment for CC so that treatment can be tailored to the individual patient.

Peutz-Jeghers syndrome (PJS) is a rare, inherited disease caused by germline mutation of the LKB1 gene. Patients with PJS develop characteristic polyps in the digestive tract and carry an elevated risk of cancers in multiple organs, including the intestinal tract. While LKB1 is capable of phosphorylating AMPK and regulates the mTOR pathway, it is also known to be a multitasking protein that can influence other cellular processes, including cell polarity. We hypothesized that there may be other biological pathways directly or indirectly affected by the loss of LKB1 in PJS and aimed to investigate this possibility through transcriptional profiling of polyps harvested from an Lkb1(+/-) mouse model of PJS and from PJS patients. We identified alterations in the mRNA level of a wide range of genes, including some that are involved in Wnt signalling (Wnt5a, Wif1, Dixdc1, Wnt11, Ccnd1, and Ccnd2), although we did not observe nuclear localization of β-catenin in over 93 human PJS intestinal polyps or in 24 gastric polyps from Lkb1(+/-) mice. Among these genes, WNT5A, a non-canonical and non-transforming Wnt, is consistently up-regulated in both Lkb1(+/-) mice and human PJS polyps at a high level. We performed in situ hybridization to further define the spatial expression pattern of WNT5A and observed a strong signal in the stroma of mouse and human polyps compared to no or very low expression in the mucosa. Our findings indicate that WNT5A plays an important role in PJS polyposis.

Transforming growth factor-â (TGF-â) signalling plays a key role in colorectal cancer (CRC). Bone morphogenetic protein-4 (BMP4) is a member of the TGF-â family of signal transduction molecules. To examine if germline mutation in BMP4 causes CRC we analysed 504 genetically enriched CRC cases (by virtue of early-onset disease, family history of CRC) for mutations in the coding sequence of BMP4. We identified three pathogenic mutations, p.R286X (g.8330C>T), p.W325C (g.8449G>T) and p.C373S (g.8592G>C), amongst the CRC cases which were not observed in 524 healthy controls. p.R286X localizes to the N-terminal of the TGF-â1 prodomain truncating the protein prior to the active domain. p.W325C and p.C373S mutations are predicted from protein homology modelling with BMP2 to impact deleteriously on BMP4 function. Segregation of p.C373S with adenoma and hyperplastic polyp in first-degree relatives of the case suggests germline mutations may confer a juvenile polyposis-type phenotype. These findings suggest mutation of BMP4is a cause of CRC and the value of protein-based modelling in the elucidation of rare disease-causing variants. © 2010 Wiley-Liss, Inc.

Tissue destruction characterizes infection with Mycobacterium tuberculosis (Mtb). Type I collagen provides the lung's tensile strength, is extremely resistant to degradation, but is cleaved by matrix metalloproteinase (MMP)-1. Fibroblasts potentially secrete quantitatively more MMP-1 than other lung cells. We investigated mechanisms regulating Mtb-induced collagenolytic activity in fibroblasts in vitro and in patients. Lung fibroblasts were stimulated with conditioned media from Mtb-infected monocytes (CoMTb). CoMTb induced sustained increased MMP-1 (74 versus 16 ng/ml) and decreased tissue inhibitor of metalloproteinase (TIMP)-1 (8.6 versus 22.3 ng/ml) protein secretion. CoMTb induced a 2.7-fold increase in MMP-1 promoter activation and a 2.5-fold reduction in TIMP-1 promoter activation at 24 hours (P = 0.01). Consistent with this, TIMP-1 did not co-localize with fibroblasts in patient granulomas. MMP-1 up-regulation and TIMP-1 down-regulation were p38 (but not extracellular signal-regulated kinase or c-Jun N-terminal kinase) mitogen-activated protein kinase-dependent. STAT3 phosphorylation was detected in fibroblasts in vitro and in tuberculous granulomas. STAT3 inhibition reduced fibroblast MMP-1 secretion by 60% (P = 0.046). Deletion of the MMP-1 promoter NF-κB-binding site abrogated promoter induction in response to CoMTb. TNF-α, IL-1β, or Oncostatin M inhibition in CoMTb decreased MMP-1 secretion by 65, 63, and 25%, respectively. This cytokine cocktail activated the same signaling pathways in fibroblasts and induced MMP-1 secretion similar to that induced by CoMTb. This study demonstrates in a cellular model and in patients with tuberculosis that in addition to p38 and NF-κB, STAT3 has a key role in driving fibroblast-dependent unopposed MMP-1 production that may be key in tissue destruction in patients.

Optical imaging of tissue autofluorescence has the potential to provide rapid label-free screening and detection of surface tumors for clinical applications, including when combined with endoscopy. Quantitative imaging of intensity-based contrast is notoriously difficult and spectrally resolved imaging does not always provide sufficient contrast. We demonstrate that fluorescence lifetime imaging (FLIM) applied to intrinsic tissue autofluorescence can directly contrast a range of surface tissue tumors, including in gastrointestinal tissues, using compact, clinically deployable instrumentation achieving wide-field fluorescence lifetime images of unprecedented clarity. Statistically significant contrast is observed between cancerous and healthy colon tissue for FLIM with excitation at 355 nm. To illustrate the clinical potential, wide-field fluorescence lifetime images of unstained ex vivo tissue have been acquired at near video rate, which is an important step towards real-time FLIM for diagnostic and interoperative imaging, including for screening and image-guided biopsy applications.

Little is known about the expression of stem cell markers in normal liver and colorectal liver metastases (CLM). The aim of this paper is to assess whether patterns of stem cell marker expression differ between normal liver tissue and CLM and to determine whether a clinical model of liver regeneration induced by portal vein embolization (PVE) has any influence on these patterns of expression in both regenerated liver tissue and cancer.Immunohistochemistry was used to provide semi-quantitative analysis of patterns of expression in tissue samples of liver and tumor tissue pre- and post-PVE in 23 patients with CLM. CD133, CD44 and Oct4 were studied.There was no expression of CD133, CD44 or Oct4 in normal liver tissue before PVE but there was high expression of CD133 and CD44 in CLM. PVE had no significant influence on stem cell marker expression either in regenerated liver tissue or in tumor when compared with pre-PVE samples.Liver regeneration following PVE does not seem to involve stem cells. Stem cell marker expression by CLM supports the stem cell theory of carcinogenesis which is not influenced by PVE.

Summary DNA polymerase ε (POLE) is a four-subunit complex and the major leading strand polymerase in eukaryotes. Budding yeast orthologs of POLE3 and POLE4 promote Polε processivity in vitro but are dispensable for viability in vivo. Here, we report that POLE4 deficiency in mice destabilizes the entire Polε complex, leading to embryonic lethality in inbred strains and extensive developmental abnormalities, leukopenia, and tumor predisposition in outbred strains. Comparable phenotypes of growth retardation and immunodeficiency are also observed in human patients harboring destabilizing mutations in POLE1. In both Pole4−/− mouse and POLE1 mutant human cells, Polε hypomorphy is associated with replication stress and p53 activation, which we attribute to inefficient replication origin firing. Strikingly, removing p53 is sufficient to rescue embryonic lethality and all developmental abnormalities in Pole4 null mice. However, Pole4−/−p53+/− mice exhibit accelerated tumorigenesis, revealing an important role for controlled CMG and origin activation in normal development and tumor prevention., Graphical Abstract, Highlights • Pole4−/− mice exhibit impaired development and defective lymphocyte maturation • Pole4 is crucial for maintaining the stability of the Polε complex • Polε hypomorphy causes replication stress via inefficient origin activation • p53 inactivation rescues all major developmental defects in Pole4-deficient mice, Bellelli et al. report that Pole4 deficiency in mice or POLE1 mutations in humans result in Pol Epsilon complex instability, replication stress, and inefficient origin activation. As a consequence, Pol Epsilon hypomorphic mice exhibit aberrant growth and development, lymphopenia, and tumor predisposition, which can be rescued by deleting p53.

Clear-cell renal cell carcinoma (ccRCC) exhibits a broad range of metastatic phenotypes that have not been systematically studied to date. Here, we analyzed 575 primary and 335 metastatic biopsies across 100 patients with metastatic ccRCC, including two cases sampledat post-mortem. Metastatic competence was afforded by chromosome complexity, and we identify 9p loss as a highly selected event driving metastasis and ccRCC-related mortality (p = 0.0014). Distinct patterns of metastatic dissemination were observed, including rapid progression to multiple tissue sites seeded by primary tumors of monoclonal structure. By contrast, we observed attenuated progression in cases characterized by high primary tumor heterogeneity, with metastatic competence acquired gradually and initial progression to solitary metastasis. Finally, we observed early divergence of primitive ancestral clones and protracted latency of up to two decades as a feature of pancreatic metastases. S.T. and H.X. are funded by Cancer Research UK (CRUK) (C50947/A18176). S.T., T.C., J.L., and M.G. are funded by the NIH Research (NIHR) Biomedical Research Centre (BRC) at the Royal Marsden Hospital and Institute of Cancer Research (A109). J.I.L. is funded by the Ministerio de Economia y Competitividad (MINECO, SAF2016-79847-R). M.S., A.S., J.L., R.F., L.A., and L.S. are funded by the Royal Marsden Cancer Charity. K.L. is funded by UK Medical Research Council (MR/P014712/1). N.M. receives funding from CRUK, Rosetrees, and the NIHR BRC at University College London Hospitals. C.S is Royal Society Napier Research Professor. C.S. is funded by Cancer Research UK (TRACERx and CRUK Cancer Immunotherapy Catalyst Network), the CRUK Lung Cancer Centre of Excellence, Stand Up 2 Cancer (SU2C), the Rosetrees and Stoneygate Trusts, NovoNordisk Foundation (ID 16584), the Breast Cancer Research Foundation (BCRF), the European Research Council (THESEUS), Marie Curie Network PloidyNet, the NIHR BRC at University College London Hospitals, and the CRUK University College London Experimental Cancer Medicine Centre. The work presented in this manuscript was funded by Cancer Research UK (grant reference number C50947/A18176), Ventana Medical Systems (grant reference numbers 10467 and 10530), the Kidney Cancer Fund of The Royal Marsden Cancer Charity, NIHR BRC at the Royal Marsden Hospital and Institute of Cancer Research (grant reference number A109), and the Francis Crick Institute, which receives its core funding from Cancer Research UK (FC001202), the UK Medical Research Council (FC001202), and the Wellcome Trust (FC001202). In particular, we acknowledge the support of the Advanced Sequencing Facility and the High-Performance Computing at the Francis Crick Institute. This project was enabled through access to the MRC eMedLab Medical Bioinformatics infrastructure, supported by the Medical Research Council (grant number MR/L016311/1).

Strong gain-of-function mutations have not been identified in humans in the FSH receptor (FSHR), whereas such mutations are common among many other G protein-coupled receptors. In order to predict consequences of such mutations on humans, we first identified constitutively activated mutants of the mouse (m) Fshr and then expressed them under the human anti-Müllerian hormone promoter in transgenic mice or created knock-in mutation into the mouse genome. We show here that mutations of Asp580 in the mFSHR significantly increase the basal receptor activity. D580H and D580Y mutations of mFSHR bind FSH, but the activity of the former is neither ligand-dependent nor promiscuous towards LH/human choriogonadotropin stimulation. Transgenic expression of mFshrD580H in granulosa cells leads to abnormal ovarian structure and function in the form of hemorrhagic cysts, accelerated loss of small follicles, augmented granulosa cell proliferation, increased estradiol biosynthesis, and occasional luteinized unruptured follicles or teratomas. The most affected mFshrD580H females are infertile with disturbed estrous cycle and decreased gonadotropin and increased prolactin levels. Increased estradiol and prolactin apparently underlie the enhanced development of the mammary glands, adenomatous pituitary growth, and lipofuscin accumulation in the adrenal gland. The influence of the mFSHRD580Y mutation is milder, mainly causing hemorrhagic cysts in transgenic mFSHRD580Y and mFSHRD580Y -knock-in mice. The results demonstrate that gain-of-function mutations of the FSHR in mice bring about distinct and clear changes in ovarian function, informative in the search of similar mutations in humans.

Summary SpyCEP is a Streptococcus pyogenes protease that cleaves CXCL8/IL-8 and its activity is associated with human invasive disease severity. We investigated the role of SpyCEP in S. pyogenes necrotizing fasciitis and respiratory tract infection in mice using isogenic strains differing only in SpyCEP expression. SpyCEP cleaved human CXCL1, 2, 6 and 8 plus murine CXCL1 and 2 at a structurally conserved site. Mice were infected in thigh muscle with a strain of S. pyogenes that expresses a high level of SpyCEP, or with an isogenic non-SpyCEP expressing strain. SpyCEP expression by S. pyogenes hindered bacterial clear- ance from muscle, and enhanced bacterial spread, associated with cleavage of murine chemoattractant CXCL1. Mice were then infected with Lactococcus lactis strains that differed only in SpyCEP expression. In contrast to the parent L. lactis strain (lacks SpyCEP), which was avirulent when administered intramuscularly, infection with a strain that expressed SpyCEP heterologously led to dramatic systemic illness within 24 h, failure to clear bacteria from muscle and marked dissemination to other organs. In the upper airways, SpyCEP expression was required for survival of L. lactis but not S. pyogenes. However, dissemination of S. pyogenes to the lung was SpyCEP-dependent and was associated with evi- dence of chemokine cleavage. Taken together, the studies provide clear evidence that SpyCEP is neces- sary and sufficient for systemic bacterial dissemina- tion from a soft tissue focus in this model and also underlies dissemination in the respiratory tract.

Background Inflammatory mediators influence tumour progression. IL-8 has been shown to have pro-angiogenic, mitogenic and motogenic effects and several studies have demonstrated the expression of IL-8 by various human pancreatic cancer cell lines. Methods: The expression of IL-8 and IL-8 receptors was studied in 52 pancreatic adenocarcinomas and 52 pancreatic neuroendocrine tumours using immunohistochemistry. The expression of IL-8 and IL-8 receptors was also assessed in eight pancreatic adenocarcinomas and seven neuroendocrine tumours in comparison to normal pancreatic tissue using real time quantitative PCR (qRT-PCR). Results: Immunohistochemical analysis of the expression of IL-8, IL-8RA and IL-8RB in 52 pancreatic adenocarcinomas demonstrated expression in 25%, 75% and 79% of pancreatic adenocarcinomas, respectively. There was no statistically significant correlation between expression and tumour grade and stage for any of the three antigens. IL-8, IL-8RA and IL-8RB expression was detected in 21%, 63% and 92% of 52 pancreatic neuroendocrine tumours. There was no statistically significant correlation between expression and tumour grade for any of the three antigens. Using qRT-PCR, the expression of each of IL-8, IL-8RA and IL-8RB mRNA was increased in 75% of pancreatic adenocarcinomas. IL-8, IL-8RA and IL-8RB mRNA expression was also increased in 57%, 43% and 29% of pancreatic neuroendocrine tumours. Quantitatively, there was a significant increase in expression level of IL-8 in tumours of both types in comparison to normal pancreatic tissue (38.5-fold in adenocarcinomas and 43.9-fold in neuroendocrine tumours). There was also increased expression of IL-8RA in both tumour types, with higher levels in adenocarcinomas, 2.7-fold and neuroendocrine tumours, 1.7-fold. IL-8RB was slightly increased in adenocarcinomas in comparison to normal pancreas (1.4-fold), but the expression was decreased in neuroendocrine tumours compared with normal pancreas (0.9-fold). Conclusion: This is the first study to show that IL-8 and IL-8 receptors are upregulated in both pancreatic adenocarcinomas and neuroendocrine tumours, and indicate this signalling pathway may modulate tumour behaviour through autocrine and/or paracrine loops.

Background and Objectives Surgery remains the only curative option for the treatment of pancreatic and ampullary carcinomas. To examine the survival differences between ampullary and pancreatic head carcinomas after pancreaticoduodenectomy. Methods A retrospective review of patients with ampullary or pancreatic head adenocarcinoma undergoing curative resection during a 6-year period prior to 2000. Results A total of 104 patients underwent pancreaticoduodenectomy for pancreatic head and ampullary carcinomas (n = 65 and n = 39, respectively). Histologically, pancreatic cancer was worse, with more lymph node involvement and more positive resection margins and vascular and perineural invasions than found in ampullary carcinoma. The median disease-free and overall survival rates were significantly better for ampullary cancer when compared with pancreatic cancer (17 vs. 9 months [P = 0.001] and 35 vs. 24 months [P = 0.006], respectively). The actuarial 5-year disease-free and overall survival rates were 4.4% and 10.5%, respectively, for pancreatic carcinoma and 27.9% and 31.8%, respectively, for ampullary carcinoma. Multivariate analysis showed that microscopic resection margin involvement (P = 0.02) and involvement of over three nodes (P

Background and purpose: The kisspeptins are critical regulators of reproduction and a therapeutic target for reproductive disease. Intracerebroventricular (i.c.v.) or peripheral injection of kisspeptin potently stimulates the hypothalamic-pituitary gonadal (HPG) axis via gonadotrophin-releasing hormone (GnRH). However, little is known regarding the effects of kisspeptin administration on testicular function. We investigated the mechanism(s) of kisspeptin-induced testicular degeneration in the rat. Experimental approach: Kisspeptin-54 (50 nmol·day−1) was continuously administered subcutaneously (6 h to 3 days) to male Wistar rats and reproductive hormones and testicular histology analysed. We also investigated the effects of a single subcutaneous injection of 0.5, 5 or 50 nmol kisspeptin-54. In order to determine whether the testicular degeneration observed is peripherally or centrally mediated, we investigated effects of i.c.v. injections of 5 nmol kisspeptin-54 and pre-administered a GnRH-receptor antagonist (cetrorelix) to rats peripherally treated with kisspeptin-54. Key results: Continuous subcutaneous administration of kisspeptin-54 caused testicular degeneration after only 12 h, when gonadotrophins were still markedly raised, suggesting that the degeneration is independent of the desensitization of the HPG axis to kisspeptin-54. Furthermore, a single subcutaneous injection of kisspeptin-54 caused dose-dependent testicular degeneration. Continuous kisspeptin-54 administration is thus not required to cause testicular degeneration. Pretreatment with cetrorelix blocked kisspeptin-induced testicular degeneration, and a single i.c.v. injection of kisspeptin-54 caused testicular degeneration, suggesting it is GnRH-mediated. Conclusions and implications: Kisspeptin-induced testicular degeneration appears to be centrally mediated, and result from acute hyper-stimulation of the HPG axis. Doses must be carefully considered if kisspeptin is to be used therapeutically. Mandarin translation of abstract

Objective To characterize possible endometrial defects in infertile women with isolated PCO morphology. Design Prospective study. Setting An academic hospital with an IVF unit. Patient(s) Women with primary unexplained infertility and isolated PCO, fertile women, and women with infertility secondary to male factor. Intervention(s) Thirty-one women (fertile and with male factor infertility) had endometrial sampling across the menstrual cycle. Nine fertile women and 10 infertile women with isolated PCO had sampling on day LH +7, adjusted for histologic dating. Main Outcome Measure(s) Expression of αvβ3 and its ligand, osteopontin, were determined using real-time quantitative polymerase chain reaction and immunohistochemistry. In vitro regulation of osteopontin was assessed using the Ishikawa cell line. Result(s) Cyclic variations revealed a fall in integrin αvβ3 mRNA during the secretory phase with concomitant up-regulation of osteopontin mRNA. Immunohistochemistry on day LH +7 demonstrated a significant reduction in expression of osteopontin in the isolated PCO group with no difference in expression of αvβ3. In vitro studies confirmed up-regulation of osteopontin by estrogen with no apparent effect of androgen. Conclusion(s) These results demonstrate an apparent reduction of osteopontin expression, important in cell–cell adhesion, during the window of implantation in infertile women with isolated PCO morphology.