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Objectives: Here, we aim at describing the pattern of care, survival outcome and prognostic factors of ABC patients (pts) receiving third-line chemotherapy. Methods: Institutional registries across three academic medical centers were retrospectively reviewed. Kaplan–Meier estimators were used to calculate survival, the log-rank test to make comparisons, and the Cox proportional hazard models to assess the progostic impact of variables. Results: Among 101 pts included in the analysis. 68 (67.3%), 19 (18.8%) and 14 (13.8%) had intrahepatic and extrahepatic cholangiocarcinoma and gallbladder cancer, respectively. Atotal of 63 (62.3%) pts received monochemotherapy, while 38 (37.6%) were treated with adoublet. The median OS and PFS were 5 and 3 months, respectively. Disease control rate was achieved in 23 (22.7%) pts, with 2 (2%) partial responses. Grade 3–4 treatment-related adverse events were reported in 22 (21.7%) pts. At multivariate analysis, ECOG PS (p

Colorectal cancer (CRC) is one of the leading causes of cancer-related death worldwide. Despite recent therapeutic advancements, resistance to 5-fluorouracil (5-FU) remains a major obstacle to the successful treatment of this disease. We have previously identified the ribosomal protein uL3 as a key player in the cell response to 5-FU, and loss of uL3 is associated with 5-FU chemoresistance. Natural products, like carotenoids, have shown the ability to enhance cancer cell response to drugs and may provide a safer choice to defeat chemoresistance in cancer. Transcriptome analysis of a cohort of 594 colorectal patients revealed a correlation between uL3 expression and both progression-free survival and response to treatment. RNA-Seq data from uL3-silenced CRC cells demonstrated that a low uL3 transcriptional state was associated with an increased expression of specific ATP-binding cassette (ABC) genes. Using two-dimensional (2D) and three-dimensional (3D) models of 5-FU-resistant CRC cells stably silenced for uL3, we investigated the effect of a novel therapeutic strategy by combining β-carotene and 5-FU using nanoparticles (NPs) as a drug delivery system. Our results indicated that the combined treatment might overcome 5-FU chemoresistance, inducing cell cycle arrest in the G2/M phase and apoptosis. Furthermore, the combined treatment significantly reduced the expression levels of analyzed ABC genes. In conclusion, our findings suggest that β-carotene combined with 5-FU may be a more effective therapeutic approach for treating CRC cells with low levels of uL3.

Aim: To apply extended ctDNA-based RAS genotyping to clinical criteria for improving the selection of patients eligible for anti-EGFR-based rechallenge in a real-world setting. Methods: ctDNA testing was prospectively applied to RASwt mCRC progressed after a first-line anti-EGFR-containing regimen and at least one other line. The primary endpoint was the objective response rate. Results: Among ten enrolled patients, the anti-EGFR rechallenge resulted in an objective response rate and disease control rate of 70% and 90%. The median progression-free survival was 11.3 months and overall survival was not reached. Compared with a historical cohort retreated with anti-EGFR agents based on clinical criteria, the ctDNA-driven approach resulted in a higher chance of achieving an objective response and longer survival. Conclusions: Blood-based RASwt status may enrich metastatic colorectal cancer more likely to benefit from anti-EGFR-based rechallenge. RAS genotyping in ctDNA represents a feasible, fast, and cost-effective tool to be implemented in the clinic for advancing precision medicine.

Melanoma is a deadly form of cancer characterized by remarkable therapy resistance. Analyzing the transcriptome of MAPK inhibitor sensitive- and resistant-melanoma, we discovered that APAF-1 is negatively regulated by MITF in resistant tumors. This study identifies the MITF/APAF-1 axis as a molecular driver of MAPK inhibitor resistance. A drug-repositioning screen identified quinacrine and methylbenzethonium as potent activators of apoptosis in a context that mimics drug resistance mediated by APAF-1 inactivation. The compounds showed anti-tumor activity in invitro and invivo models, linked to suppression of MITF function. Both drugs profoundly sensitize melanoma cells to MAPK inhibitors, regulating key signaling networks in melanoma, including the MITF/APAF-1 axis. Significant activity of the two compounds in inhibiting specific epigenetic modulators of MITF/APAF-1 expression, such as histone deacetylases, was observed. In summary, we demonstrate that targeting the MITF/APAF-1 axis may overcome resistance and could be exploited as a potential therapeutic approach to treat resistant melanoma.

Massimiliano Salati,1,2 Luigi Marcheselli,1 Carlo Messina,3 Valeria Merz,3,4 Marco Messina,5 Pietro Carotenuto,6 Francesco Caputo,1 Fabio Gelsomino,1 Andrea Spallanzani,1 Luca Reggiani Bonetti,7 Stefania Caramaschi,7 Gabriele Luppi,1 Massimo Dominici,1 Michele Ghidini8 1Division of Oncology, Department of Oncology and Hematology, University Hospital of Modena, Modena, Italy; 2PhD Program Clinical and Experimental Medicine, University of Modena and Reggio Emilia, Modena, Italy; 3Department of Medical Oncology, Santa Chiara Hospital, Trento, Italy; 4Digestive Molecular Clinical Oncology Research Unit, University of Verona, Verona, Italy; 5Oncology Unit, Fondazione San Raffaele-Giglio, Cefalu’, Palermo, Italy; 6Telethon Institute of Genetics and Medicine, Pozzuoli, 80078, Napoli, Italy; 7Pathology Section, University Hospital of Modena, Modena, Italy; 8Medical Oncology Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, ItalyCorrespondence: Massimiliano Salati, PhD Program Clinical and Experimental Medicine, University Hospital of Modena, Modena Cancer Centre, via del Pozzo 71, Modena, 41125, Italy, Tel +39/0594223808, Fax +39/0594222647, Email massimiliano.salati@unimore.itBackground: The role of second-line chemotherapy in advanced biliary cancers (ABCs) has only recently been established in phase III randomized trial and the optimal selection of patients most likely to benefit from it remains challenging.Methods: A cohort of 98 ABC treated second-line chemotherapy was used as a developmental dataset to identify covariates independently associated with overall survival (OS). Kaplan–Meier analysis was used to investigate the association between variables and OS and those retaining statistically significance were combined in a multiplexed score.Results: The following pretreatment variables were independently associated with OS: ECOG PS > 0, peritoneal disease, LDH > 430 UI/L, albumin < 3.5 gr/dL, gamma-GT > 100 UI/L, sodium < 140 mEq/L, absolute lymphocyte count < 1000/mmc, and PFS to first-line < 6 months. Based on these results, a scoring system was developed that identified three subgroups with statistically different OS: low-risk (mOS 18 months), intermediate-risk (mOS 9.4 months) and high-risk (mOS 2.9 months) (p < 0.001). The prognostic model was both internally and externally validated in a multicentre cohort of 120 ABCs.Conclusion: The Modena score is a multiplexed scoring system capable of accurately risk-stratified ABCs treated with second-line chemotherapy. Based on its reproducibility, usability and generalizability, it has the potential for assisting therapeutic decision-making in the clinic and risk-stratification in future trials.Graphical Abstract: Keywords: biliary tract cancer, chemotherapy, second-line, prognostic score, survival

606 Background: Despite the improved outcome achieved by the addition of the anti-PD-L1 durvalumab to standard chemotherapy, the vast majority of BTC do not benefit from chemo-immunotherapy. Immunosuppressive microenvironment is a dominant feature of BTC, involved in tumour progression and drug resistance. Here, we investigated the biological role and treatment implications of the adenosine-producing enzyme CD73 in a clinically-annotated cohort of BTC. CD73, an ecto-5’-nucleotidase (NT5E), creates an immunosuppressive tumour-promoting microenvironment by converting ATP to adenosine. Methods: Immunohistochemistry for CD73, CD4/CD8 and FOXP3 as well as whole-exome and transcriptomic sequencing were performed on resected specimens of 80 BTC (Illumina Platform). Spatial Transcriptomics was performed by using Visium Spatial Gene Expression-10x Genomics). Silencing of CD73 was obtained by transient transfection od CD73-siRNA, while genetic Knock-out by using CRISPR-Cas system technology in two BTC cell lines. Tumor growth was assessed in 2D and in 3D cell culture by using MTS assay and spheroid growth analysis before and after treatment with selected drugs. Statistical and Survival, correlation analyses were performed. Results: High CD73 expression (CD73high) was associated with older age (>70 years, p=0.01), gallbladder subsite (p=0.03), and nodal involvement (p=0.04). CD73high tumours were significantly enriched in infiltrating FOXP3+ T lymphocytes (phigh status was independent predictor of poorer prognosis at the multivariate analysis (p=0,03) together with ECOG PS ≥2 (p=0,001) and the pathological stage (p=0,025) and was associated with a remarkably shorter RFS in patients treated with adjuvant chemotherapy (p=0,011). At the transcriptomic level, CD73high tumours were significantly enriched in upregulated EMT, TNF-alfa/NFKB, hypoxia and G2/M checkpoint signaling pathways and p53, BMI1, MEL18, EGFR and K-RAS genes. In in vitro models, siRNA-mediated depletion and CRISPR-CAS9 gene KO of CD73 sensitized both BTC 2D and 3D culture to cisplatin/gemcitabine treatment. The pharmacological inhibition of CD73 by AMCP improved the sensitivity of BTC cell lines to cisplatin/gemcitabine treatment. Finally, Spatially resolved transcriptomics of CD73high revealed a critical role of CD73 in tumor immunity and therapeutic response. Conclusions: We showed that CD73high BTC display aggressive biological features, poorer prognosis and resistance to standard chemotherapy. The therapeutic targeting of this adenosinergic ectonucleotidase by clinically-available compounds has the potential to enhance the efficacy of conventional treatment in BTC.

BACKGROUND AND AIMS Sirtuin 1 (SIRT1) is a complex NAD+ -dependent protein deacetylase known to act as a tumor promoter or suppressor in different cancers. Here, we describe a mechanism of SIRT1-induced destabilization of primary cilia in cholangiocarcinoma (CCA). APPROACH AND RESULTS A significant overexpression of SIRT1 was detected in human CCA specimens and CCA cells including HuCCT1, KMCH, and WITT1 as compared with normal cholangiocytes (H69 and NHC). Small interfering RNA (siRNA)-mediated knockdown of SIRT1 in HuCCT1 cells induced cilia formation, whereas overexpression of SIRT1 in normal cholangiocytes suppressed ciliary expression. Activity of SIRT1 was regulated by presence of NAD+ in CCA cells. Inhibition of NAD -producing enzyme nicotinamide phosphoribosyl transferase increased ciliary length and frequency in CCA cells and in SIRT1-overexpressed H69 cells. Furthermore, we also noted that SIRT1 induces the proteasomal mediated degradation of ciliary proteins, including α-tubulin, ARL13B, and KIF3A. Moreover, overexpression of SIRT1 in H69 and NHC cells significantly induced cell proliferation and, conversely, SIRT1 inhibition in HuCCT1 and KMCH cells using siRNA or sirtinol reduced cell proliferation. In an orthotopic transplantation rat CCA model, the SIRT1 inhibitor sirtinol reduced tumor size and tumorigenic proteins (glioma-associated oncogene 1, phosphorylated extracellular signal-regulated kinase, and IL-6) expression. CONCLUSIONS In conclusion, these results reveal the tumorigenic role of SIRT1 through modulation of primary cilia formation and provide the rationale for developing therapeutic approaches for CCA using SIRT1 as a target.

Thyroid cancer is the most common type of endocrine cancer, and its prevalence continue to rise. Non-metastatic thyroid cancer patients are successfully treated. However, looking for new therapeutic strategies is of great importance for metastatic thyroid cancers that still lead to death. With respect to this, the tumor microenvironment (TME), which plays a key role in tumor progression, should be considered as a new promising therapeutic target to hamper thyroid cancer progression. Indeed, thyroid tumors consist of cancer cells and a heterogeneous and ever-changing niche, represented by the TME, which contributes to establishing most of the features of cancer cells. The TME consists of extracellular matrix (ECM) molecules, soluble factors, metabolites, blood and lymphatic tumor vessels and several stromal cell types that, by interacting with each other and with tumor cells, affect TME remodeling, cancer growth and progression. Among the thyroid TME components, cancer-associated fibroblasts (CAFs) have gained more attention in the last years. Indeed, recent important evidence showed that thyroid CAFs strongly sustain thyroid cancer growth and progression by producing soluble factors and ECM proteins, which, in turn, deeply affect thyroid cancer cell behavior and aggressiveness. Hence, in this article, we describe the thyroid TME, focusing on the desmoplastic stromal reaction, which is a powerful indicator of thyroid cancer progression and an invasive growth pattern. In addition, we discuss the origins and features of the thyroid CAFs, their influence on thyroid cancer growth and progression, their role in remodeling the ECM and their immune-modulating functions. We finally debate therapeutic perspectives targeting CAFs.

Breast cancer-associated fibroblasts (BCAFs), the most abundant non-cancer stromal cells of the breast tumor microenvironment (TME), dramatically sustain breast cancer (BC) progression by interacting with BC cells. BCAFs, as well as myofibroblasts, display an up regulation of activation and inflammation markers represented by α-smooth muscle actin (α-SMA) and cyclooxygenase 2 (COX-2). BCAF aggregates have been identified in the peripheral blood of metastatic BC patients. We generated an in vitro stromal model consisting of human primary BCAFs grown as monolayers or 3D cell aggregates, namely spheroids and reverted BCAFs, obtained from BCAF spheroids reverted to 2D cell adhesion growth after 216 h of 3D culture. We firstly evaluated the state of activation and inflammation and the mesenchymal status of the BCAF monolayers, BCAF spheroids and reverted BCAFs. Then, we analyzed the MCF-7 cell viability and migration following treatment with conditioned media from the different BCAF cultures. After 216 h of 3D culture, the BCAFs acquired an inactivated phenotype, associated with a significant reduction in α-SMA and COX-2 protein expression. The deactivation of the BCAF spheroids at 216 h was further confirmed by the cytostatic effect exerted by their conditioned medium on MCF-7 cells. Interestingly, the reverted BCAFs also retained a less activated phenotype as indicated by α-SMA protein expression reduction. Furthermore, the reverted BCAFs exhibited a reduced pro-tumor phenotype as indicated by the anti-migratory effect exerted by their conditioned medium on MCF-7 cells. The deactivation of BCAFs without drug treatment is possible and leads to a reduced capability of BCAFs to sustain BC progression in vitro. Consequently, this study could be a starting point to develop new therapeutic strategies targeting BCAFs and their interactions with cancer cells.

Melanoma is a deadly form of cancer characterized by high aggressiveness and remarkable therapy-resistance. The inactivation of apoptosis constitutes a common strategy adopted by cancer cells to survive death-stimulating drugs. We examined the transcriptome of human melanoma samples responders and resistant to MAPK inhibitors and discovered that APAF-1, the main component of apoptosome, is downregulated in resistant tumors. The decreased expression of APAF-1 was correlated with high levels of the melanoma survival oncogene MITF . We therefore demonstrated that the MITF/APAF-1 axis could be relevant in driving resistance to MAPK inhibitor treatments. A drug-repositioning screen identified Quinacrine and Methylbenzethonium as potent activators of apoptosis in a context that mimics drug resistance mediated by APAF-1 inactivation. Our findings demonstrated the pro-apoptotic and tumor-suppressor activity of the compounds in a large panel of melanoma cells, including patient-derived cells and in vivo models, where the two drugs showed remarkable suppression of MITF function. Quinacrine and Methylbenzethonium profoundly sensitize BRAF and NRAS mutant melanoma cells to MAPK-pathway inhibitors, thus indicating their pharmacological relevance in melanoma. Transcriptomic profiles of melanoma cells revealed that both compounds regulate key-signaling networks in melanoma, including the MITF gene network. In summary, we demonstrate that inhibiting a driver of MAPK inhibitor resistance could improve current approaches of targeted melanoma therapy.

Massimiliano Salati,1,2 Francesco Caputo,1 Cinzia Baldessari,1 Pietro Carotenuto,3 Marco Messina,4 Stefania Caramaschi,5 Massimo Dominici,1 Luca Reggiani Bonetti5 1Department of Oncology and Hematology, University Hospital of Modena, Modena, Italy; 2PhD Program Clinical and Experimental Medicine, University of Modena and Reggio Emilia, Modena, Italy; 3Department of Genomics, Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy; 4Department of Oncology, Fondazione Istituto G. Giglio, Cefalu, Italy; 5Department of Medical and Surgical Sciences for Children and Adults, University of Modena and Reggio Emilia – AOU Policlinico of Modena, Modena, ItalyCorrespondence: Massimiliano SalatiDepartment of Oncology and Hematology, University Hospital of Modena, Via del Pozzo 71, Modena, 41125, ItalyTel +390594223808Fax +390594222647Email massimiliano.salati@unimore.itAbstract: Intrahepatic cholangiocarcinoma (iCCA) is an anatomically and biologically distinct entity with a rising incidence and a poor prognosis on conventional treatments. Surgery followed by adjuvant chemotherapy is a potentially curative option in resectable cases, while palliative-intent chemotherapy is the standard-of-care in the advanced setting. Technological advances through massive parallel sequencing have enabled a deeper understanding of disease biology with the identification of several druggable molecular vulnerabilities in nearly 50% of cases. Among them, gene fusions involving the fibroblast growth factor receptor 2 (FGFR2) are the most therapeutically exploited so far with a number of Phase II clinical trials investigating FGFR2 inhibitors showing unprecedented efficacy results in this molecular subgroup. Over the last year, these efforts have culminated in the US FDA-approval of pemigatinib and infigratinib, the first two oral selective FGFR2 targeted agents for previously treated, locally advanced or metastatic iCCA driven by FGFR2 fusion or rearrangements. While first-line Phase III trials are currently underway to test these targeted approach against standard-of-care chemotherapy, translational studies are trying to better understand primary and secondary resistance mechanisms in order to optimize FGFR2 blockade in iCCA. In this article, we extensively reviewed the current evidence on the biological rationale, as well as preclinical and clinical development of FGFR inhibitors in iCCA.Keywords: biliary cancer, cholangiocarcinoma, intrahepatic, FGFR2, targeted therapy, precision medicine

MicroRNAs (miRNAs) are small noncoding RNAs playing a fundamental role in the regulation of gene expression. Evidence accumulating in the past decades indicate that they are capable of simultaneously modulating diverse signaling pathways involved in a variety of pathophysiological processes. In the present review, we provide a comprehensive overview of the function of a highly conserved group of miRNAs, the miR-181 family, both in physiological as well as in pathological conditions. We summarize a large body of studies highlighting a role for this miRNA family in the regulation of key biological processes such as embryonic development, cell proliferation, apoptosis, autophagy, mitochondrial function, and immune response. Importantly, members of this family have been involved in many pathological processes underlying the most common neurodegenerative disorders as well as different solid tumors and hematological malignancies. The relevance of this miRNA family in the pathogenesis of these disorders and their possible influence on the severity of their manifestations will be discussed. A better understanding of the miR-181 family in pathological conditions may open new therapeutic avenues for devasting disorders such as neurodegenerative diseases and cancer.

The nucleolus is the site of ribosome biogenesis and has been recently described as important sensor for a variety of cellular stressors. In the last two decades, it has been largely demonstrated that many chemotherapeutics act by inhibiting early or late rRNA processing steps with consequent alteration of ribosome biogenesis and activation of nucleolar stress response. The overall result is cell cycle arrest and/or apoptotic cell death of cancer cells. Our previously data demonstrated that ribosomal protein uL3 is a key sensor of nucleolar stress activated by common chemotherapeutic agents in cancer cells lacking p53. We have also demonstrated that uL3 status is associated to chemoresistance, down-regulation of uL3 makes some chemotherapeutic drugs ineffective. Here, we demonstrate that in colon cancer cells, the uL3 status affects rRNA synthesis and processing with consequent activation of uL3-mediated nucleolar stress pathway. Transcriptome analysis of HCT 116p53&minus, /&minus, cells expressing uL3 and of a cell sub line stably depleted of uL3 treated with Actinomycin D suggests a new extra-ribosomal role of uL3 in the regulation of autophagic process. By using confocal microscopy and Western blotting experiments, we demonstrated that uL3 acts as inhibitory factor of autophagic process, the absence of uL3 is associated to increase of autophagic flux and to chemoresistance. Furthermore, experiments conducted in presence of chloroquine, a known inhibitor of autophagy, indicate a role of uL3 in chloroquine-mediated inhibition of autophagy. On the basis of these results and our previous findings, we hypothesize that the absence of uL3 in cancer cells might inhibit cancer cell response to drug treatment through the activation of cytoprotective autophagy. The restoration of uL3 could enhance the activity of many drugs thanks to its pro-apoptotic and anti-autophagic activity.

473 Background: CD73, an ecto-5’-nucleotidase (NT5E), creates an immunosuppressive tumour-promoting microenvironment by converting ATP to adenosine. The expression of CD73 has been linked to poorer patients (pts) outcome across several cancer types and the targeted inhibition of this immunoinhibitory protein has been recently advanced to clinical development. However, the clinicopathologic role of CD73 as well as its potential implications are largely unexplored in BC. Methods: The expression of CD73 was assessed by immunohistochemistry on both tumour (tCD73) and stromal tissue (sCD73) of a clinically-annotated cohort of radically-resected BC and scored for staining intensity as follows: +1, +2 and +3. RNAseq was performed on RNA isolated from surgical specimens. Differences between groups were evaluated using the Chi-square test. Survival functions were estimated by the Kaplan-Meier method and comparisons were made using the log-rank test. The Cox proportional hazards model was used to assess the impact of covariates on survival outcomes. Results: CD73 immunohistochimichal expression was evaluated on resected specimens of 70 BC pts. 43 pts (61%) were tCD73-positive, while 44 pts (62%) were sCD73-positive. Among the former group, the intensity score was 1+ in 19 pts (44%), 2+ in 16 pts (37%), 3+ in 10 pts (23%), while in the latter group was 1+ in 22 pts (50%), 2+ in 10 pts (22%) and 3+ in 12 pts (27%). CD73 positivity was associated with older age (> 70 years, p = 0.01), gallbladder subsite (p = 0.03), and nodal involvement (p = 0.04). Patients with tCD73-positive BC experienced a significantly shorter relapse-free survival (8,4 vs 39,4 months; p = 0.016) and overall survival (60,7 vs 13,7 months; p = 0.017). Notably, high tCD73 expressors (score 3+) displayed the poorest prognosis (12,03 months; p = 0.023). When evaluated on univariate and multivariate analysis, tCD73 positivity was an independent prognostic factor for both relapse-free survival (p = 0.038) and overall survival (p = 0.023), together with ECOG PS and pTNM stage. Whole-transcriptome sequencing is ongoing to correlate CD73 expression with cancer-related pathways. Conclusions: In this study, we provided a clinicopathologic characterization of CD73 expression in resected BC, demonstrating that tCD73 is an independent negative prognostic biomarker in this disease. Although these findings are in need of a validation in larger dataset, they foster novel combination of anti-CD73 agents with conventional therapy in the poorer-prognosis subset of CD73-positive BC.

Several experimental strategies in the treatment of cancer include drug alteration of cell cycle regulatory pathways as a useful strategy. Extra-ribosomal functions of human ribosomal protein L3 (uL3) may affect DNA repair, cell cycle arrest and apoptosis. In the present study, we demonstrated that uL3 is required for the activation of G1/S transition genes. Luciferase assays established that uL3 negatively regulates the activity of E2F1 promoter. Induced ribosome-free uL3 reduces Cyclin D1 mRNA and protein levels. Using protein/protein immunoprecipitation methods, we demonstrated that uL3 physically interacts with PARP-1 affecting E2F1 transcriptional activity. Our findings led to the identification of a new pathway mediated by uL3 involving E2F1 and Cyclin D1 in the regulation of cell cycle progression.

MicroRNAs (miRNAs) are attractive therapeutic targets and promising candidates as molecular biomarkers for various therapy-resistant tumors. However, the association between miRNAs and drug resistance in melanoma remains to be elucidated. We used an integrative genomic analysis to comprehensively study the miRNA expression profiles of drug-resistant melanoma patients and cell lines. MicroRNA-181a and -181b (miR181a/b) were identified as the most significantly down-regulated miRNAs in resistant melanoma patients and cell lines. Re-establishment of miR-181a/b expression reverses the resistance of melanoma cells to the BRAF inhibitor dabrafenib. Introduction of miR-181 mimics markedly decreases the expression of TFAM in A375 melanoma cells resistant to BRAF inhibitors. Furthermore, melanoma growth was inhibited in A375 and M14 resistant melanoma cells transfected with miR-181a/b mimics, while miR-181a/b depletion enhanced resistance in sensitive cell lines. Collectively, our study demonstrated that miR-181a/b could reverse the resistance to BRAF inhibitors in dabrafenib resistant melanoma cell lines. In addition, miR-181a and -181b are strongly down-regulated in tumor samples from patients before and after the development of resistance to targeted therapies. Finally, melanoma tissues with high miR-181a and -181b expression presented favorable outcomes in terms of Progression Free Survival, suggesting that miR-181 is a clinically relevant candidate for therapeutic development or biomarker-based therapy selection.

Background and Aims: Changes in single microRNA (miRNA) expression have been associated with chemo-resistance in biliary tract cancers (BTCs). However, a global assessment of the dynamic role of the microRNome has never been performed to identify potential therapeutic targets that are functionally relevant in the BTC cell response to chemotherapy. Approach and Results: High-throughput screening (HTS) of 997 locked nucleic acid miRNA inhibitors was performed in six cholangiocarcinoma cell lines treated with cisplatin and gemcitabine (CG) seeking changes in cell viability. Validation experiments were performed with mirVana probes. MicroRNA and gene expression was assessed by TaqMan assay, RNA-sequencing, and in situ hybridization in four independent cohorts of human BTCs. Knockout of microRNA was achieved by CRISPR-CAS9 in CCLP cells (MIR1249KO) and tested for effects on chemotherapy sensitivity in vitro and in vivo. HTS revealed that MIR1249 inhibition enhanced chemotherapy sensitivity across all cell lines. MIR1249 expression was increased in 41% of cases in human BTCs. In validation experiments, MIR1249 inhibition did not alter cell viability in untreated or dimethyl sulfoxide–treated cells; however, it did increase the CG effect. MIR1249 expression was increased in CD133+ biliary cancer cells freshly isolated from the stem cell niche of human BTCs as well as in CD133+ chemo-resistant CCLP cells. MIR1249 modulated the chemotherapy-induced enrichment of CD133+ cells by controlling their clonal expansion through the Wnt-regulator FZD8. MIR1249KO cells had impaired expansion of the CD133+ subclone and its enrichment after chemotherapy, reduced expression of cancer stem cell markers, and increased chemosensitivity. MIR1249KO xenograft BTC models showed tumor shrinkage after exposure to weekly CG, whereas wild-type models showed only stable disease over treatment. Conclusions: MIR1249 mediates resistance to CG in BTCs and may be tested as a target for therapeutics.

Although biliary tract cancers (BTCs) are known to have an inflammatory component, a detailed characterisation of immune-related transcripts has never been performed. In these studies, nCounter PanCancer Immune Profiling Panel was used to assess the expression of 770 immune-related transcripts in the tumour tissues (TTs) and matched adjacent tissues (ATs) of resected BTCs. Cox regression analysis and Kaplan–Meier methods were used to correlate findings with relapse-free survival (RFS). The first analysis in the TT and AT of an exploratory set (n = 22) showed deregulation of 39 transcripts associated with T-cell activation. Risk of recurrence was associated with a greater number of genes deregulated in AT in comparison to TT. Analysis in the whole set (n = 53) showed a correlation between AT cytotoxic T-lymphocyte antigen-4 (CTLA4) expression and RFS, which maintained statistical significance at multivariate analysis. CTLA4 expression correlated with forkhead box P3 (FOXP3) expression, suggesting enrichment in T regulatory cells. CTLA4 is known to act by binding to the cluster of differentiation 80 (CD80). No association was seen between AT CD80 expression and RFS. However, CD80 expression differentiated prognosis in patients who received adjuvant chemotherapy. We showed that the immunomodulatory transcriptome is deregulated in resected BTCs. Our study includes a small number of patients and does not enable to draw definitive conclusions; however, it provides useful insights into potential transcripts that may deserve further investigation in larger cohorts of patients. Transcript Profiling Nanostring data have been submitted to GEO repository: GSE90698 and GSE90699., Highlights • BTCs harbour a derangement of immune-related transcripts with an important role for the cytotoxic T-lymphocyte antigen-4 (CTLA4) axis. • CTLA4 expression in the peritumoural areas correlates with outcome and represents a potential promising prognostic factor. • Our data suggest that immunotherapy may have an impact in BTCs as a mean to re-address the host immune response to the tumour.

Background FOLFIRINOX-regime is a combination-chemotherapy that provides the best clinical benefit in pancreatic ductal adenocarcinoma (PDAC) patients, but is associated with severe toxicity. Aim of this study is to explore the role of miRNAs as modulators of chemosensitivity and their potential as biomarkers of sensitivity to FOLFIRINOX-therapy. Methods HTS of 997 LNA-MIR-inhibitors was performed in PDAC cell lines treated with a combination of Fluorouracil (F), Oxaliplatin (O) and Irinotecan (I) that mimics FOLFIRINOX-regime. Validation experiments were performed with miRvana probes. Apoptosis was measured by flow-cytometry and western-blotting. Knock-out of microRNA was achieved by CRISPR-CAS9 in MiaPaca2 cells. HITS-CLIP assay was used to identify MIR1307 target site. Drug sensitivity was tested in xenograft models. Plasma MIR1307 was assessed by ddPCR. Results 41 and 84 miRNA-inhibitors enhanced FOI activity by > 30% (p Conclusions We identified MIR1307 as a potential modulator of sensitivity to FOI-chemotherapy in PC. MIR1307 inhibition impairs the ability of the cells to recover from chemotherapy damage and therefore enhances its activity. Legal entity responsible for the study The authors. Funding Pancreatic Cancer UK Research Innovation Fund, Cancer Research UK. Disclosure All authors have declared no conflicts of interest.

Pancreatic cancer is an aggressive cancer of the digestive system, which is becoming a serious health problem worldwide. Overall survival for patients with pancreatic cancer is poor, mainly due to a lack of biomarkers to enable early diagnosis and a lack of prognostic markers that can inform decision-making, facilitating personalized treatment and an optimal clinical outcome. ncRNAs play an important role in pancreatic carcinogenesis. Here we review the literature on the role of ncRNAs as biomarkers in pancreatic cancer. We focus on the significance of ncRNAs as markers for early diagnosis, as prognostic biomarkers able to inform clinical management and as targets for novel therapeutics for patients with pancreatic cancer.

The development of stratified retinal cell architecture is highly conserved in all vertebrates, implying that a common fundamental molecular mechanism is involved in the generation of the organized retina. However, the detailed molecular mechanisms of retinal development are not fully understood. Here we have identified the Xenopus ortholog of prune and show that it is expressed in both differentiating and differentiated retinal domains during development. Interestingly, these spatial and temporal expression patterns coincide with the expression of prune binding partners, the NM23 family members. Overexpression of prune in retinal precur- sor cells significantly increases the ratio of Müller glial cells as observed by modulation of NM23 activity (Mochizuki et al., 2009). However, a mutated form of prune that has replacement of four aspartate (D) res- idues (D'Angelo et al., 2004), essential for phosphodiesterase activity, does not exhibit gliogenic activity. Our observations suggest that Xenopus prune may regulate Müller gliogenesis through phosphodiesterase- mediated regulation of NM23 family members.

The fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) signaling axis plays an important role in normal organ, vascular and skeletal development. Deregulation of FGFR signaling through genetic modification or overexpression of the receptors (or their ligands) has been observed in numerous tumor settings. Preclinical and clinical data showed that inhibition of FGFR signaling may result in antitumor effects, thus confirming the validity of the FGF/FGFR axis as a potential therapeutic target. Pemigatinib (INCB-054828), developed by Incyte Corporation, is an orally bioavailable inhibitor of FGFR types 1, 2 and 3 (FGFR-1/2/3) with antineoplastic activity. Pemigatinib is able to inhibit FGFR-1/2/3, which results in the inhibition of FGFR signaling pathways, thus causing an antiproliferative effect in FGFR-1/2/3- overexpressing tumor cells. The FIGHT (FIbroblast Growth factor receptor in oncology and Hematology Trials) clinical trial program is currently assessing the efficacy and safety of pemigatinib in patients with several types of tumors. The drug candidate has been granted orphan drug designation for the treatment of cholangiocarcinoma both in the United States and Europe, and has also received breakthrough therapy designation in the United States for this indication. An update on the preclinical and clinical pharmacology of pemigatinib is provided in this review.

ntroduction: FOLFIRINOX-regime is a combination-chemotherapy that provides the best clinical benefit in pancreatic cancer (PC) patients, but is associated with severe toxicity. Aim of this study is to explore the role of miRNAs (MIR) as modulators of chemosensitivity and their potential as biomarkers of sensitivity to FOLFIRINOX-chemotherapy. Methods: High-throughput-screening (HTS) of 997 LNA-MIR-inhibitors was performed in PC cell lines (Capan1, MiaPaCa2) treated with a combination of Fluorouracil (F), Oxaliplatin (O) and Irinotecan (I) that mimics FOLFIRINOX-regime. Cell viability was monitored by CellTiter-Blue assay. Validation experiments were carried out with miRvana probes. MIR expression was assessed by TaqMan-assay. Apoptosis was measured by Flow-cytometry and western-blotting. Knock-out of microRNA was acheived by CRISPR-CAS9 in MiaPaca2 cells (MIR1307KO). Results: 41 and 84 miRNA-inhibitors enhanced FOI activity by >30% (p Citation Format: Pietro Carotenuto, Domenico Zito, Maria C. Previdi, Maya Raj, Matteo Fassan, Andrea Lampis, Francesco Scalafani, Andrea Lanese, Ian Said-Huntingford, Jens C. Hahne, Kate Young, Ruwaida Begum, Zakaria Ethiar, Andrew Wotherspoon, Naureen Starling, Anguraj Sadanandam, David Cunningham, Ian Chau, Paul Workman, Rajesh Chopra, Nicola Valeri, Chiara Braconi. MIR1307 mediates pancreatic cancer resistance to FOLFIRINOX chemotherapy by affecting response to DNA damage [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4977.

Renal-cell cancer (RCC) is an heterogeneous disease consisting of different subtypes that show peculiar histological features and genetic alterations. Although inherited or familial predisposition occurs in less than 4% of renal cancers, most of the available information on the genetic alterations involved in the pathogenesis of RCC derives from the study of the inherited forms of kidney cancer: von Hippel-Lindau ( VHL gene), hereditary papillary renal carcinoma ( MET proto-oncogene), hereditary leiomyomatosis and renal-cell cancer ( fumarate hydratase gene), and Birt–Hogg–Dube ( BHD gene) syndromes. Such genetic alterations have also been detected in sporadic RCCs. In particular, inactivation of VHL gene by mutation or hypermethylation has been found in up to 70% of sporadic clear-cell RCC, and it has been associated with increased hypoxia-inducible factor (HIF) activity. The knowledge of these deregulated genes and their downstream pathways provides the rationale for the development of target-based approaches for RCC.

A genetic interaction between PRUNE and NM23/NDPK has been postulated in Drosophila melanogaster. Many have focused on Drosophila for the genetic combination between PRUNE "knock down" and AWD/NM23 fly mutants bearing the P97S mutation (K-pn, Killer of PRUNE mutation). We postulated a role for PRUNE-NM23 interactions in vertebrate development, demonstrating a physical interaction between the human PRUNE and NM23-H1 proteins, and partially characterizing their functional significance in cancer progression. Here, we present an initial analysis towards the functional characterization of the PRUNE-NM23 interaction during mammalian embryogenesis. Our working hypothesis is that PRUNE, NM23-H1 and their protein-protein interaction partners have important roles in mammalian brain development and adult brain function. Detailed expression analyses from early mouse brain development to adulthood show significant co-expression of these two genes during embryonic stages of brain development, especially focusing on the cortex, hippocampus, midbrain and cerebellum. We hypothesize that their abnormal expression results in an altered pathway of activation, influencing protein complex formation and its protein partner interactions in early embryogenesis. In the adult brain, their function appears concentrated towards their enzyme activities, wherein biochemical variations can result in brain dysfunction.

Primary biliary cholangitis (PBC) is an autoimmune slowly progressive liver disease characterized by the destruction of intrahepatic bile ducts, which gradually evolves into cirrhosis and liver failure (1). Ursodeoxycholic acid (UDCA) is the first choice for the treatment of PBC patients and has shown to significantly reduce the need for liver transplantation (2). The precise aetiology of PBC is not known, but is considered to be related to a combination of genetic, epigenetic and environmental factors.

Patients with metastatic colorectal carcinoma (mCRC) carrying activating mutations of the KRAS gene do not benefit from treatment with anti-epidermal growth factor receptor (EGFR) monoclonal antibodies. Therefore, KRAS mutation testing of mCRC patients is mandatory in the clinical setting for the choice of the most appropriate therapy. Co-amplification-at-lower denaturation-temperature PCR (COLD-PCR) is a novel modification of the conventional PCR method that selectively amplifies minority alleles from a mixture of wild-type and mutant sequences irrespective of the mutation type or position within the sequence. In this study, we compared the sensitivity of a COLD-PCR method with conventional PCR/sequencing and the real-time PCR-based Therascreen kit to detect KRAS mutations. By using dilutions of KRAS mutant DNA in wild-type DNA from colon cancer cell lines with known KRAS status, we found that Fast COLD-PCR is more sensitive than the conventional PCR method, showing a sensitivity of 2.5% in detecting GA and GT mutations. The detection of GC transversions was not improved by either Fast COLD-PCR or Full COLD-PCR. We next analyzed by COLD-PCR, conventional PCR and Therascreen 52 formalin-fixed paraffin-embedded samples from mCRC patients. Among 36 samples with30% tumor cells, 8 samples were negative by conventional PCR, Therascreen and Fast COLD-PCR; 20 mutations identified by conventional PCR were confirmed by Therascreen and Fast COLD-PCR; 8 cases undetermined by conventional PCR were all confirmed to carry KRAS GA or GT mutations by using either Therascreen or Fast COLD-PCR. Conventional PCR was able to detect only 2 KRAS mutations among 16 samples with30% tumor cells (12.5%), whereas Therascreen and Fast COLD-PCR identified 6 mutants (37.5%). These data suggest that Fast COLD-PCR has a higher clinical sensitivity as compared with conventional PCR in detecting GC to AT changes in the KRAS gene, which represent90% of the mutations of this oncogene in CRC.

Aims: Patients with metastatic colorectal carcinoma (mCRC) carrying activating mutations of the KRAS gene do not benefit from treatment with anti-EGF receptor monoclonal antibodies. Therefore, KRAS mutation testing of mCRC patients is mandatory in the clinical setting to aid in the choice of appropriate therapy. Materials & methods: We developed a cost-effective approach for the determination of KRAS mutations in codons 12 and 13 in clinical practice based on a sensitive PCR/sequencing technique and the commercially available real-time PCR-based Therascreen® kit (DxS Ltd). Results & conclusion: The PCR/sequencing test was able to detect 10% mutant DNA in a background of wild-type DNA. By using this assay, we determined the mutational status of KRAS in 527 out of 540 (97.6%) formalin-fixed paraffin-embedded tissues from mCRC patients. PCR/sequencing was not conclusive in 13 cases, in which low-intensity peaks suggestive of potential mutations were identified. The DxS assay, which showed a sensitivity of 1%, identified mutations in 11 out of 13 inconclusive cases. Interestingly, five of these 11 cases showed high levels of DNA fragmentation. No significant difference was found in the ability of PCR/sequencing and DxS to identify KRAS mutations within 160 cases with more than 30% tumor cells. However, in 24 samples with less than 30% tumor cells, DxS showed an higher sensitivity. In conclusion, our findings suggest that PCR/sequencing can be used for mutational analysis of the majority of tumor samples that have more than 30% tumor cell content, whereas more sensitive and expensive tests should be reserved for inconclusive cases and for samples with a low amount of tumor cells.

Colon carcinoma with rhabdoid characteristics is a rare, malignant tumor whose molecular alterations have not been clarified yet. We report a novel case of a colon adenocarcinoma with rhabdoid features in a 71-year-old woman, localized to the right colon and associated with local lymph node and liver metastasis. The patient died within 8 months from surgery despite target chemotherapy. The tumor was enriched in cells with a typical rhabdoid-type morphology displaying a marked and diffuse vimentin staining. Cells were also positive for epidermal growth factor receptor (EGFR), p53, Ki67, and β-catenin and negative for cytokeratin 20/cytokeratin 7, E-cadherin, and CDX2. Remarkably, the promoter regions of 4 of 5 specific genes that define the so-called "CpG island methylator phenotype," including mutL homolog 1 (MLH1), were methylated. Consistently, microsatellite instability was detected. A BRAF V600E mutation and no KRAS mutations were identified. Finally, 4 tumor suppressor gene promoters CDH1, CDKN1B, CDKN1C, and MGMT were not methylated. This is the first case of a colorectal carcinoma with rhabdoid features, "CpG island methylator phenotype," high microsatellite instability associated with a BRAF mutation, and patient poorer outcome. © 2011 Elsevier Inc. All rights reserved.

The epidermal growth factor receptor (EGFR) is expressed in the majority of non- small-cell lung cancer (NSCLC). However, only a restricted subgroup of NSCLC patients respond to treatment with the EGFR tyrosine kinase inhibitor (EGFR TKI) gefitinib. Clinical trials have demonstrated that patients carrying activating mutations of the EGFR significantly benefit from treatment with gefitinib. In particular, mutations of the EGFR TK domain have been shown to increase the sensitivity of the EGFR to exogenous growth factors and, at the same time, to EGFR TKIs such as gefitinib. EGFR mutations are more frequent in patients with particular clinical and pathological features such as female sex, nonsmoker status, adenocarcinoma histology, and East Asian ethnicity. A close correlation was found between EGFR mutations and response to gefitinib in NSCLC patients. More importantly, randomized Phase III studies have shown the superiority of gefitinib compared with chemotherapy in EGFR mutant patients in the first-line setting. In addition, gefitinib showed a good toxicity profile with an incidence of adverse events that was significantly lower compared with chemotherapy. Therefore, gefitinib is a major breakthrough for the management of EGFR mutant NSCLC patients and represents the first step toward personalized treatment of NSCLC. © 2011 Carotenuto et al, publisher and licensee Dove Medical Press Ltd.

Analysis by DNA microarrays has led to the identification of molecular subtypes of breast carcinomas that show a distinct expression profile. Several studies have demonstrated that this 'intrinsic subtype' classification has a strong prognostic value. In addition, gene expression profiling techniques have been used to identify gene signatures that could be associated with the outcome of breast cancer patients. Several different genomic tests have been shown to better define the prognosis of early-stage breast cancer patients as compared with conventional clinical and pathological characteristics of the tumors, and some assays are already commercially available. However, it must be emphasized that the prognostic power of these genetic classifiers has not been confirmed yet in prospective trials. Genetic signatures that might predict the activity of specific chemotherapy agents have also been developed by using gene expression profiling techniques. The same approach has been used to identify gene signatures associated with the activation of oncogenic pathways that might represent targets for molecular therapy of breast cancer. By using these approaches, gene expression techniques might significantly improve our ability to predict the risk of recurrence and to tailor the treatment for each individual breast cancer patient. Copyright © 2010 S. Karger AG.

Triple negative breast cancer is a subtype of breast cancer that lacks expression of an estrogen receptor (ER), a progesterone receptor (PR), and HER2. It is characterized by its unique molecular profile, aggressive behavior, and distinct pattern of metastasis. Epidemiological studies show a high prevalence of triple negative breast cancer among younger women and those of African descent. Although sensitive to chemotherapy, early relapse is common, and a predilection for visceral metastasis, including brain metastasis, has been described. Gene-expression profiling approaches demonstrated that triple negative breast cancer is a heterogeneous group of diseases composed of different, molecularly distinct subtypes. Although not synonymous, the majority of triple negative breast cancers carry the "basal-like" molecular profile on gene-expression arrays. However, several studies have shown that triple negative breast cancer includes tumors with a non-basal expression profile and, in particular, the "normal-breast," the "multiple marker negative," and the recently identified "claudin-negative" subtypes. Target-based agents, including epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), and poly-ADP-ribose polymerase (PARP) inhibitors, are currently in clinical trials and hold promise in the treatment of this aggressive disease. © 2010 by Begell House, Inc.

Vandetanib is an oral inhibitor of vascular endothelial growth factor receptor 2 (VEGFR-2), epidermal growth factor receptor (EGFR) and Ret tyrosine kinases involved in tumor growth, progression and angiogenesls. Phase I studies indicated that the recommended dose of vandetanib as a single agent is 300 mg/day. Rash, diarrhea, hypertension and asymptomatic Q-Tc prolongation were the most common adverse events. Four randomized phase III clinical trials evaluated the efficacy of vandetanib in non-small cell lung cancer (NSCLC) in combination with docetaxel (ZODIAC), pemetrexed (ZEAL) or as a single agent (ZEST and ZEPHYR). Only the ZODIAC trial met its primary endpoint (progression-free survival [PFS]), while no study showed an advantage in overall survival with vandetanib. No significant antitumor activity has been observed in small cell lung cancer, advanced ovarian, colorectal, breast, prostate cancer and multiple myeloma. In advanced metastatic medullary thyroid cancer, one randomized phase III clinical trial has demonstrated that vandetanib can significantly Improve response rate, PFS and time to worsening of pain. Several key questions remain to be addressed regarding the identification of clinical or molecular biomarkers predictive of response, the choice of the optimal dose or schedule of vandetanib and the safety of long-term administration. The results of ongoing trials in untreated patients with advanced NSCLC and other tumors should better define the optimal clinical application of vandetanib. Copyright © 2010 Prous Science, S.A.U. or its licensors. All rights reserved.

Current systemic therapies for breast cancer are often limited by their non-specific mechanism of action, unwanted toxicities on normal tissues and short-term efficacy due to the emergence of drug resistance. Identification of the molecular alterations in key proteins involved in breast cancer cell proliferation and survival resulted in development of various signal transduction inhibitors as new treatment strategy. Preclinical data support the use of these agents in breast cancer, including estrogen receptor positive breast cancer patients in which signalling inhibitors might prevent or treat resistance to endocrine therapy. These compounds have generally shown an acceptable toxicity profile. However, little clinical activity of signalling inhibitors as monotherapy in breast cancer patients has been reported up to now. Furthermore, the preliminary results of clinical trials of combinations of signalling inhibitors and endocrine therapies published to day are rather disappointing. These negative findings are likely due to the occurrence of mechanisms of resistance to these drugs.

The vertebrate telencephalon is composed of many architectonically and functionally distinct areas and structures, with billions of neurons that are precisely connected. This complexity is fine-tuned during development by numerous genes. To identify genes involved in the regulation of telencephalic development, a specific subset of differentially expressed genes was characterized. Here, we describe a set of cDNAs encoded by genes preferentially expressed during development of the mouse telencephalon that was identified through a functional genomics approach. Of 832 distinct transcripts found, 223 (27%) are known genes. Of the remaining, 228 (27%) correspond to expressed sequence tags of unknown function, 58 (7%) are homologs or orthologs of known genes, and 323 (39%) correspond to novel rare transcripts, including 48 (14%) new putative noncoding RNAs. As an example of this latter group of novel precursor transcripts of micro-RNAs, telencephalic embryonic subtractive sequence (TESS) 24.E3 was functionally characterized, and one of its targets was identified: the zinc finger transcription factorZFP9. The TESS transcriptome has been annotated, mapped for chromosome loci, and arrayed for its gene expression profiles during neural development and differentiation (in Neuro2a and neural stem cells). Within this collection, 188 genes were also characterized on embryonic and postnatal tissue byin situhybridization, demonstrating that most are specifically expressed in the embryonic CNS. The full information has been organized into a searchable database linked to other genomic resources, allowing easy access to those who are interested in the dissection of the molecular basis of telencephalic development.

A rapid and sensitive radiometric assay for UDP-glucuronosyl-transferase (UGT) is described. UGT substrates are incubated in 96-well plates with microsomes in the presence of [14C]UDP-glucuronic acid, and 14C-labeled glucuronidation products are separated from the unreacted nucleotide sugar by solid-phase extraction using 96-well extraction plates. The assay was validated with 15 structurally diverse UGT substrates containing acidic, phenolic, and hydroxyl reacting groups. Glucuronidation velocities for these compounds were determined using human, rat, and dog liver microsomes, and reaction kinetics were studied with 1-naphthol and 4-methylumbelliferone. Results obtained with the new assay confirmed the previously reported rank order of glucuronidation velocity of several typical UGT substrates and the finding that the glucuronidation of most of these compounds is significantly faster in dog than in human liver microsomes. UGT specificity of five compounds was determined using recombinant human UGTs. The major UGT isoforms identified were UGT1A6, UGT1A7, and UGT1A9 for 4-methylumbelliferone; UGT1A6 and UGT1A8 for 1-naphthol; UGT2B7 for naloxone; UGT1A3 and UGT2B7 for ketoprofen; and UGT1A4 for trifluoperazine. Identical results were obtained with a conventional high-performance liquid chromatography method coupled to mass spectrometric detection. The new assay should prove valuable for rapidly benchmarking recombinant UGTs and microsomal preparations from different species and tissues, identifying high-turnover compounds during drug discovery, and reaction phenotyping studies. Copyright © 2005 by The American Society for Pharmacology and Experimental Therapeutics.

1Pharmacogenomic Laboratory, INT Fondazione Pascale – CROM, Mercogliano (AV), Italy †Author for correspondence: Cell Biology & Biotherapy Unit, INT Fondazione Pascale, Naples, Italy Tel.: +39 081 590 3826 nicnorm@yahoo.com Kobunai et al. raised important questions concerning the molecular diagnostics of KRAS mutations in metastatic colorectal carcinoma (CRC) [1] that we are happy to address. In particular, they suggest that assays that are more sensitive than direct sequencing of the PCR product (PCR/sequencing) detect a higher rate of KRAS mutations even in samples with over 50% tumor cells. This phenomenon might in part be owing to the molecular heterogeneity of some CRC cells that contain clones of KRAS mutant and wild-type cells. They hypothesize, therefore, that using a limit of 30% tumor cells might lead patients to lose the benefit of treatment with an anti-EGFR agent. With regards to the points raised by Kobunai et al., we feel that it is important to underline the points discussed in the following sections. We confirmed that real-time PCR-based assays such as the DxS Therascreen kit (DxS Ltd, Manchester, UK) are more sensitive than PCR/sequencing [2]. However, our study, as well as a larger study by Tol et al. [3], found no statistically significant difference in the ability to detect KRAS mutations between DxS and PCR/sequencing in a huge cohort (a total of over 500 patients) of CRC samples with over 30% tumor cells. In a quality assessment of KRAS testing that was run in Germany, the error rate of PCR/sequencing and of more sensitive, real-time PCR-based techniques was comparable [4]. Similar data were obtained in an Italian, as yet unpublished quality assessment [Italian Association of Medical Oncology and the Italian Society of Surgical Pathology and