Search

PURPOSE To characterize the relationship between tumor-infiltrating lymphocytes (TIL), tumor mutational burden (TMB), and genetic alterations in microsatellite stable (MSS), microsatellite instability (MSI), or mutant POLE/POLD1 colon cancer. MATERIALS AND METHODS Four hundred ninety-nine resected stage I-III colon tumors treated between 2014 and 2019 were assessed for TIL; somatic mutations, copy number alterations, and structural changes in > 400 oncogenes; and MSI status. RESULTS Of the 499 tumors analyzed, 313 were MSS, 175 were MSI, and 11 had POLE/POLD1 pathogenic mutations. Both the percentage of tumors with a high level of TIL (≥ 4 lymphocytes per high-power field) and the median TMB differed significantly between the three phenotypes: MSS, 4.5% and 6 mutations/Mb; MSI, 68% and 54 mutations/Mb; POLE/POLD1, 82% and 158 mutations/Mb ( P < .05). Within each phenotype, TMB did not vary significantly with TIL level. Among MSI tumors, the median number of frameshift indels was significantly higher in tumors with high levels of TIL (20 v 17; P = .018). In the MSS group, significantly higher proportions of tumors with high levels of TIL had mutations in the transforming growth factor-β (36% v 12%; P = .01), RAS (86% v 54%; P = .02), and Hippo (7% v 1%; P = .046) pathways; in contrast, TP53 alterations were associated with low levels of TIL (74% v 43%; P = .01). CONCLUSION The association between TIL, TMB, and genetic alterations varies significantly between MSI, MSS, and mutant POLE/POLD1 colon tumors. These differences may help explain tumoral immunity and lead to predictors of response to immunotherapy.

Objective: To determine the frequency of mismatch repair deficiency in colorectal carcinoma determined by immunohistochemistry. Study Design: Cross-sectional study. Place and Duration of Study: Department of Histopathology, Armed Forces Institute of Pathology, Rawalpindi, from Aug 2018 to Jan 2019. Methodology: A total of 101 patients of adenocarcinoma of colorectum who underwent surgical resections and their characteristic and clinical data were recorded. Immunohistochemical stains were performed using antibodies MLH1, MSH2, PMS2 and MSH6. Results were interpreted and mismatch repair deficiency status of all patients was determined. Patients with loss of expression for MLH1, MSH2, PMS2 and MSH6 antibodies were observed and noted. Results: In this study, out of 101 patients with CRC, 71 (70.3%) were male and 30 (29.7%) female. The mean age was (54 years ± 15.9). Amongst the 101 cases loss of immunohistochemical staining for MMR proteins was noted in 19 patients (18.8%). The combined loss of all four antibodies was seen in one case, loss of MLH1 and PMS2 in 7, MSH2 and MSH6 in 5 and MLH1 only in 6 patients. However, no mismatch repair deficiency was detected in remaining 82 cases. According to statistical analysis no significant association between mismatch repair deficiency and variables was found. Conclusion: The frequency of mismatch repair deficiency in colorectal carcinoma patients was found to be 18.8% in our population.

Neoadjuvant chemotherapy (NACT) before radical gastrectomy is preferred for locally advanced gastric cancer (GC). However, clinical practices demonstrate that a considerable proportion of GC patients do not benefit from NACT, largely due to the lack of biomarkers for patient selection and prognosis prediction. A recent study revealed that patients with microsatellite instability-high (MSI-H) may be resistant to NACT, however, most tumors in Chinese GC patients (~ 95%) are characterized by microsatellite stability (MSS). Here, we aimed to discover new molecular biomarkers for this larger population. We performed whole-exome sequencing on 46 clinical samples (pre- and post-treatment) from 30 stage II/III MSS GC patients whose response to NACT was rigorously defined. Serum tumor markers (TMs), including AFP, CEA, CA199, CA724 and CA242 were measured during the course. High tumor mutation burden (TMB-H) and 19q12 amplification (19q12 +) were positively associated with the NACT response. When TMB and 19q12 amplification were jointly analyzed, those with TMB-H or 19q12 + showed favorable response to NACT (p = 0.035). Further, TMB-H was negatively correlated with ypN stage, lymph node metastasis, and macrophage infiltration. Patients with TMB-H showed better disease-free survival (DFS) than those with TMB-L (P = 0.025, HR = 0.1331), and this was further validated using two larger GC datasets: TCGA-STAD (p = 0.004) and ICGC-CN (p = 0.045). The combination of TMB-H and 19q12 + can serve as an early indicator of response to NACT. Superior to traditional clinical indicators, TMB-H is a robust and easily accessible candidate biomarker associated with better DFS, and can be evaluated at the time of diagnosis.

BACKGROUND Rectal cancer in adolescents and young adults (age ≤39) is increasing. Early diagnosis is a challenge in this subset of patients. OBJECTIVE This study aims to analyze the presentation pattern and outcomes of sporadic rectal cancer in adolescents and young adults. DESIGN This is a retrospective study. SETTING This study was conducted at 3 European tertiary centers. PATIENTS Data on adolescents and young adults operated on for sporadic rectal cancer (January 2008 through October 2019) were analyzed. To compare outcomes, adolescents and young adults were matched to a group of patients aged ≥40 operated on during the same period. MAIN OUTCOME MEASURES The primary outcomes measured were clinical presentation and long-term outcomes. RESULTS Sporadic rectal cancers occurred in 101 adolescents and young adults (2.4%; mean age, 33.5; range, 18-39); 51.5% were male, and a smoking habit was reported by 17.8% of patients. The rate of a family history for colorectal cancer was 25.7%, and of these patients, 24.7% were obese. Diagnosis based on symptoms was reported in 92.1% patients, and the mean time from first symptoms to diagnosis was 13.7 months. The most common symptom at diagnosis was rectal bleeding (68.8%), and 12% and 34% of the adolescents and young adults presented with locally advanced or metastatic disease at diagnosis. Consequently, 68.3% and 62.4% adolescents and young adults received neoadjuvant and adjuvant treatments. The rate of complete pathological response was 24.1%; whereas 38.6% patients had stage IV disease, and 93.1% were microsatellite stable. At a mean follow-up of 5 years, no difference in cancer-specific survival, but a lower disease-free survival was reported in adolescents and young adults (p < 0.0001) vs the matched group. Adolescents and young adults with stages I to II disease had shorter cancer-specific survival and disease-free survival (p = 0.006; p < 0.0001); with stage III disease, they had a shorter disease-free survival (p = 0.01). LIMITATIONS This study was limited by its observational, retrospective design. CONCLUSIONS The significantly delayed diagnosis in adolescents and young adults may have contributed to the advanced disease at presentation and lower disease-free survival, even at earlier stages, suggesting a higher metastatic potential than in older patients. See Video Abstract at http://links.lww.com/DCR/B537. CNCER DE RECTO EN PACIENTES ADOLESCENTES Y ADULTOS JVENES CUADRO DE PRESENTACIN CLNICA Y COMPARACIN DE DESENLACES POR CASOS EMPAREJADOS ANTECEDENTES:El cancer de recto en adolescentes y adultos jovenes (edad ≤ 39) esta aumentando. El diagnostico temprano es un desafio en este subgrupo de pacientes.OBJETIVO:Analizar el cuadro de presentacion y los desenlaces en adolescentes y adultos jovenes con cancer de recto esporadico.DISENO:Estudio retrospectivo.AMBITO:Tres centros europeos de tercer nivel.PACIENTES:Se analizaron los datos de adolescentes y adultos jovenes operados de cancer de recto esporadico (enero de 2008 - octubre de 2019). Para comparar los desenlaces se emparejo a adolescentes y adultos jovenes con un grupo de pacientes mayores de 40 anos operados en el mismo periodo de tiempo.PRINCIPALES VARIABLES ANALIZADAS:Cuadro clinico, resultados a largo plazo.RESULTADOS:Los canceres de recto esporadicos en adolescentes y adultos jovenes fueron 101 (2,4%, edad media: 33,5, rango 18-39). El 51,5% eran hombres, el 17,8% de los pacientes fumaba. El 25,7% tentia antecedentes familiares de cancer colorrectal. El 24,7% eran obesos. El diagnostico con base en los sintomas se informo en el 92,1% de los pacientes, el tiempo promedio desde los primeros sintomas hasta el diagnostico fue de 13,7 meses. El sintoma mas comun en el momento del diagnostico fue el sangrado rectal (68,8%). 12% y 34% de adolescentes y adultos jovenes presentaron enfermedad localmente avanzada o metastasica en el momento del diagnostico. Por lo tanto, el 68,3% y el 62,4% de adolescentes y adultos jovenes recibieron neoadyuvancia y adyuvancia. La tasa de respuesta patologica completa fue del 24,1%; mientras que el 38,6% estaban en estadio IV. El 93,1% eran microsatelite estable. Con una media de seguimiento de 5 anos, no se observaron diferencias en la sobrevida especifica del cancer, pero se informo una menor sobrevida libre de enfermedad en adolescentes y adultos jovenes (p

Clinicopathological features of high-frequency microsatellite instability (MSI-H) colorectal cancers (CRCs) are different from low-frequency MSI (MSI-L) and microsatellite stable (MSS) CRCs. The clinical features of MSI-L cases are unknown, and although the tumors usually show instability for dinucleotide markers, evaluation based on dinucleotides alone could lead to the misclassification of MSI-L or MSS as MSI-H. In this research, we investigated the usefulness of hypoxia-inducible factor-1α (HIF-1α) expression to discriminate MSI-L from MSS and MSI-H in human CRC. Tumor tissue from 94 CRC patients was used to determine the expression level of HIF-1α mRNA and HIF-1α protein using quantitative real-time PCR and immunohistochemistry analyses, respectively. The results indicated that HIF-1α mRNA and HIF-1α protein levels were upregulated in CRC patients compared with controls (P < 0.0001). Average HIF-1α expression in tissues with advanced stages and grades was also higher than that in earlier stages and grades. Expression of HIF-1α mRNA varied between CRC patients with different types of microsatellite instability (MSS, MSI-L and MSI-H). Taken together, our findings provide preliminary evidence that HIF-1α expression level in CRC tumors correlates with different MSI categories. HIF-1α expression may therefore represent a novel marker to separate the MSI-L group from the MSS and MSI-H groups.

CASE SUMMARY A 65-year-old man presents with new liver lesions on surveillance imaging 2 years after a right hemicolectomy for cecal adenocarcinoma. The primary tumor was pT3N1, microsatellite stable, and KRAS wild type. He completed adjuvant FOLFOX. His CEA level is 22 ng/mL. There are two 1.5-cm lesions in the right lobe near the dome of the liver and a 4-cm lesion in segment II. No luminal recurrence is detected endoscopically, and there is no evidence of peritoneal or pulmonary disease.

Immune checkpoint inhibitors changed treatment paradigms across several malignancies. With the exception of tumors with microsatellite instability (MSI-H), gastrointestinal cancers have been largely resistant to these agents. Herein, we review the data supporting the use of immunotherapy for patients with (MSI-H) colorectal tumors. We discuss ongoing research and answered questions regarding resistance and sequence of use of these agents for this disease. We discuss ongoing research efforts to augment activity of these agents in microsatellite stable colorectal cancer. We also provide an overview of the data and ongoing studies immune checkpoint inhibitors in the treatment of anal cancer.

Dosage effect is one of the common mechanisms of somatic copy number alteration in the development of colorectal cancer, yet the roles of dosage-sensitive genes (DSGs) in colorectal cancer (CRC) remain to be characterized more deeply. In this study, we developed a five-step pipeline to identify DSGs and analyzed their characterization in CRC. Results showed that our pipeline performed better than existing methods, and the result was significantly overlapped between solid tumor and cell line. We also found that the top five DSGs (PSMF1, RAF1, PTPRA, MKRN2, and ELP3) were associated with the progression of CRC. By analyzing the characterization, DSGs were enriched in driver genes and they drove sub-pathways of CRC. In addition, immune-related DSGs are associated with CRC progression. Our results also showed that the CRC samples affected by high microsatellites have fewer DSGs, but a higher overlap with DSGs in microsatellite low instability and microsatellite stable samples. In addition, we applied DSGs to identify potential drug targets, with the results showing that 22 amplified DSGs were more sensitive to four drugs. In conclusion, DSGs play an important role in CRC, and our pipeline is effective to identify them., Graphical Abstract, Xu and colleagues developed a five-step pipeline to identify dosage-sensitive genes and analyzed their characterization in colorectal cancer. The results proved that the pipeline was effective. Additionally the dosage-sensitive genes were proven to be associated with colorectal cancer progression, drove the cancer sub-pathway, and were sensitive to drugs.

Supplemental Digital Content is available in the text., Grade 3 (G3, poorly differentiated) is an important treatment-decision factor in stage II colon cancer, but no unified diagnostic criteria are established. According to previous studies, an intratumoural poorly differentiated area with no glandular formation (POR) that fills the microscopic field of a ×40 objective lens was an essential factor that defined G3. We aimed to prospectively validate this in a randomized controlled study of adjuvant chemotherapy (SACURA trial). We enrolled 991 patients with stage II colon cancer. POR was graded according to the ×40 objective lens rule and the intensity of poorly differentiated clusters (GradePOR), and its prognostic power was compared with that of the conventional tumor grade on the basis of predominant histology rule (Gradeconv). According to GradePOR, 313, 526, and 152 tumors were classified as G1POR, G2POR, and G3POR, respectively, and the 5-year relapse-free survival (RFS) rates were 91.1%, 82.9%, and 74.7%, respectively (P

Patients with colorectal liver metastases (CLM) commonly receive neoadjuvant chemotherapy (NACT) prior to surgical resection. NACT may induce immunogenic cell death with subsequent recruitment of T-cells to the tumor microenvironment, which could be exploited by immune checkpoint inhibition (ICI). In theory, this could expand the use of ICI to obtain responses also in microsatellite stable colorectal cancer, but evidence to suggest optimal treatment schedules are lacking. In this study, densities of total-, cytotoxic-, helper- and regulatory T-cells were quantified by immunohistochemistry in resected CLM from 92 patients included in the OSLO-COMET trial (NCT01516710). All but one patient had microsatellite stable tumors (91/92). Associations between T-cell densities and clinicopathological parameters were analyzed. Fluoropyrimidine-based NACT (in most cases with addition of oxaliplatin or irinotecan) was administered to 45 patients completed median 8 weeks prior to surgical resection. No overall association was found between NACT administration and intratumoral T-cell densities. However, within the NACT group, a short time interval (

Circulating tumor DNA (ctDNA) is increasingly being investigated as a tool to detect minimal residual disease in resected, stage I-III colorectal cancer. Recent ctDNA studies have indicated that detection of ctDNA following surgery for resectable colorectal cancer confers a significantly higher risk of recurrence than those with negative ctDNA postoperatively. In those with postoperative ctDNA positivity, clearance of minimal residual disease with adjuvant chemotherapy is a positive prognostic indicator. Lastly, ctDNA has demonstrated superior sensitivity to the conventional blood tumor marker carcinoembryonic antigen (CEA) and can offer median lead times of up to 11 months for radiographic detection of recurrence during the surveillance of resected, stage I-III colorectal cancer. In metastatic colorectal cancer (mCRC), there is growing evidence to suggest that plasma ctDNA can be used to monitor tumor response to conventional chemotherapy as well. The present case series demonstrated that plasma ctDNA is a predictor of tumor response to immunotherapy in patients with mCRC that are microsatellite stable or microsatellite instability high. Plasma ctDNA could serve as a dynamic marker of immunotherapy response even in colorectal tumors that were CEA non-producers. Overall, these findings add to ongoing efforts to establish the role of plasma ctDNA in monitoring response to immunotherapy in CRC.

Purpose:To analytically and clinically validate microsatellite instability (MSI) detection using cell-free DNA (cfDNA) sequencing.Experimental Design:Pan-cancer MSI detection using Guardant360 was analytically validated according to established guidelines and clinically validated using 1,145 cfDNA samples for which tissue MSI status based on standard-of-care tissue testing was available. The landscape of cfDNA-based MSI across solid tumor types was investigated in a cohort of 28,459 clinical plasma samples. Clinical outcomes for 16 patients with cfDNA MSI-H gastric cancer treated with immunotherapy were evaluated.Results:cfDNA MSI evaluation was shown to have high specificity, precision, and sensitivity, with a limit of detection of 0.1% tumor content. In evaluable patients, cfDNA testing accurately detected 87% (71/82) of tissue MSI-H and 99.5% of tissue microsatellite stable (863/867) for an overall accuracy of 98.4% (934/949) and a positive predictive value of 95% (71/75). Concordance of cfDNA MSI with tissue PCR and next-generation sequencing was significantly higher than IHC. Prevalence of cfDNA MSI for major cancer types was consistent with those reported for tissue. Finally, robust clinical activity of immunotherapy treatment was seen in patients with advanced gastric cancer positive for MSI by cfDNA, with 63% (10/16) of patients achieving complete or partial remission with sustained clinical benefit.Conclusions:cfDNA-based MSI detection using Guardant360 is highly concordant with tissue-based testing, enabling highly accurate detection of MSI status concurrent with comprehensive genomic profiling and expanding access to immunotherapy for patients with advanced cancer for whom current testing practices are inadequate.See related commentary by Wang and Ajani, p. 6887

RATIONALE: Loss of DNA mismatch repair function has long been known in various malignancies, particularly colorectal cancer. However, microsatellite instability (MSI) testing was rarely requested in Thailand. Recently, the US Food and Drug Administration (FDA) has approved pembrolizumab, an antibody to PD-1 receptor, as an alternative treatment for high MSI (MSI-H) and/or MMR (mismatch repair)-deficient solid tumors. We report our recent observation on MSI testing in Thailand. MATERIALS AND METHODS: Data was collected from Chulalongkorn GenePRO Center, Faculty of Medicine, Chulalongkorn University, during July 2013 and July 2017. MSI testing was performed, using 5 microsatellite markers (BAT-25, BAT-26, D2S123, D5S346 and D17S250). The number, source, and result of samples underwent MSI assay were analyzed. RESULTS: Requests for MSI testing have increased significantly in recent years. The shift started in 2015 when the MMR status was found to predict clinical benefit with the immune checkpoint blockade. There were 118 (75.2%) colorectal, 11 (7%) gastric, and 28 (17.8%) other cancers tested. MSI-H, MSI-L, and microsatellite stable (MSS) tumors were detected in 18 (11.5%), 11 (7%), and 128 (81.5%) patients, respectively. Of the 18 MSI-H cancers; 13 (72.2%), 4 (22.2%), and 1 (5.6%) were colorectal, gastric, and gynecologic malignancy, respectively. BAT25 and BAT26 markers were unstable in all MSI-H tumors. CONCLUSION: We have experienced increasing demand for MSI testing in Thai patients at Chulalongkorn GenePRO Center. Colorectal cancers were most frequently tested, and accounted for the highest percentage among the MSI-H cancers. Keywords: microsatellite instability, mismatch repair, immunotherapy, cancers Address Correspondence to author: Chinachote Teerapakpinyo, PhD Chulalongkorn GenePRO Center,Faculty of Medicine, Chulalongkorn University 1873, Rama 4 Rd., Pathumwan, Bangkok 10330, Thailand. email: Chinachote.T@chula.ac.th Received: May 28, 2018 Revision received: June 1, 2018 Accepted after revision: July 17, 2018 BKK Med J 2018;14(2): 1-5. DOI: 10.31524/bkkmedj.2018.09.001

Background: Colorectal cancer (CRC) is one of the most common cancers worldwide with high number of mortality every year. Microsatellite instability (MSI) is a considerable feature of CRC which affects prognosis and treatment. High level of MSI or MSI-high (MSI-H) colorectal cancer has better prognosis and immunotherapy response, while microsatellite stable (MSS) CRC has better response to 5-fluorouracil (5-FU)-based chemotherapy. More studies are needed, specifically on MSS CRC which has worse prognosis, to further reveal biological differences and similarities between MSS and MSI colorectal cancer, which may equip us with the knowledge to develop more promising therapeutic approaches to target both types or be more effective for each type. Methods: We aimed to find affected biological processes and their regulators in both type, MSS and MSI-H, of CRC; as well as reveal specific ones in each type. We applied meta- and network analysis on freely available transcriptome data in MSS and MSI-H colorectal cancer from gene expression omnibus (GEO) database to detect common differentially expressed genes (DEGs) and critical biological processes and predict their most significant regulators. Results: Our results demonstrate considerable up and downregulation in cell cycle and lipid catabolism processes, respectively; and introduced MYC and FOXM1 as two central and up-stream regulators of DEGs in both type of CRC. Chemokine-mediated processes displayed up-regulation in MSI-H type, while metastasis-related processes showed more activation in MSS CRC. Additionally, DACH1 and TP53 were detected as two important transcription factors that differentially expressed just in MSS and MSI-H, respectively. Conclusion: Our results can explain why MSI and MSS CRC display different immunotherapy response, prognosis, and metastasis feature. Moreover, our predicted up-stream regulators in the regulatory networks may be promising therapeutic targets.

Immune checkpoint blockade has emerged as an effective therapeutic strategy for patients with advanced cancer. Identification of biomarkers associated with treatment efficacy will help to select patients more likely to respond to this approach. High levels of microsatellite instability, tumor expression of PD-L1, high tumor mutation burden, and increased tumor-infiltrating lymphocytes have all been associated with response to checkpoint inhibitor blockade. The purpose of this study was to determine if a subset of microsatellite-stable endometrioid endometrial carcinomas have higher immune cell infiltrates and/or expression of PD-L1. PD-L1 expression and characterization of immune cell infiltrates were analyzed in 132 microsatellite stable, FIGO grade 2 endometrioid carcinomas. PD-L1 was positive in 48% (63/132) of the tumors. Tumor cell expression of PD-L1 was significantly associated with lymphatic/vascular invasion and deep myometrial invasion. PD-L1 expression was especially prominent at the invasive front and in foci of tumor-associated squamous metaplasia. Twenty-one cases (16% of the total) with more diffuse and/or especially strong PD-L1 expression were identified. This PD-L1 high subset was associated with significantly higher numbers of tumor-associated CD3+ and CD8+ lymphocytes. Only one tumor in the PD-L1 high subset harbored a POLE mutation. PTEN immunohistochemical loss, a common event in endometrioid-type endometrial carcinoma and associated with local immune suppression in melanoma, was not associated with PD-L1 expression or lymphocyte/macrophage infiltration of the tumor. These results suggest that a subset of microsatellite-stable endometrial cancers has higher expression of PD-L1 and increased tumor-associated CD3+ and CD8+ lymphocytes, characteristics more commonly associated with endometrial cancers with high levels of microsatellite instability. These results suggest that screening strategies to select only microsatellite instability-high advanced endometrial cancers for checkpoint inhibitor therapy might exclude patients who could potentially benefit from this therapeutic approach.

BackgroundThe generation of long-term durable tumor immunity and prolonged disease-free survival depends on the ability to generate and support CD8+ central memory T-cells. Microsatellite-stable colon cancer is resistant to currently available immunotherapies; thus, development of novel mechanisms to increase both lymphocyte infiltration and central memory formation are needed to improve outcomes in these patients. We have previously demonstrated that both interleukin-2 (IL-2) and LIGHT (TNFSF14) independently enhance antitumor immune responses and hypothesize that combination immunotherapy may increase the CD8+ central memory T-cell response.MethodsMurine colorectal cancer tumors were established in syngeneic mice. Tumors were treated with control, soluble, or liposomal IL-2 at established intervals. A subset of animal tumors overexpressed tumor necrosis superfamily factor LIGHT (TNFSF14). Peripheral blood, splenic, and tumor-infiltrating lymphocytes were isolated for phenotypic studies and flow cytometry.ResultsTumors exposed to a combination of LIGHT and IL-2 experienced a decrease in tumor size compared with IL-2 alone that was not demonstrated in wild-type tumors or between other treatment groups. Combination exposure also increased splenic central memory CD8+ cells compared with IL-2 administration alone, while not increasing tumor-infiltrating lymphocytes. In the periphery, the combination enhanced levels of circulating CD8 T-cells and central memory T-cells, while also increasing circulating T-regulatory cells.ConclusionsCombination of IL-2, whether soluble or liposomal, with exposure to LIGHT results in increased CD8+ central memory cells in the spleen and periphery. New combination immunotherapy strategies that support both effector and memory T-cell functions are critical to enhancing durable antitumor responses and warrant further investigation.

Gastric malignancy – one of the five most deadliest types of cancer – exceeds annual cases by a million worldwide since 2017. Automated screening tools may help speed up the screening and clinical procedures. In this paper, we propose a binary classification approach to classify gastrointestinal cancer tissues, namely Microsatellite Instable (MSI) and Microsatellite Stable (MSS) through stacked generalization based ensemble Deep Neural Network (DNN)11Authors contributed equally to the work.. Using a dataset of size 192, 315 images, we achieve an overall accuracy of 94.91% and sensitivity of 95.95%. Our results outperform previous works.

AimsAnalysis of microsatellite instability (MSI) is strongly recommended in endometrial cancer (EC) and colorectal cancer to screen for Lynch syndrome, to predict prognosis and to determine optimal treatment and follow-up. In a large monoinstitutional series of ECs, we evaluated the reliability and accuracy of Idylla assay, a rapid, fully automated system to detect MSI, and we compared its performance with two routine reference methods.MethodsWe evaluated MSI status in 174 formalin-fixed, paraffin-embedded EC tissue samples using immunohistochemistry (IHC) for mismatch repair (MMR) proteins and Idylla assay. Samples with discordant or equivocal results were analysed with a third technique, the Promega MSI kit.ResultsIdylla MSI assay and IHC were highly concordant (overall agreement: 154/170=90.59%, 95% CI 85.26% to 94.12%). However, in four samples, MMR-IHC staining was equivocal; moreover, 16 cases showed discordant results, that is, MMR deficient using IHC and microsatellite stable using Idylla. These 20 samples were reanalysed using the MSI-Promega kit, which showed the same results of Idylla assay in 18/20 cases (overall agreement: 90%, 95% CI 69.90% to 97.21%).ConclusionsOur results suggest that IHC is an efficient method to determine MMR status in ECs. However, the Idylla MSI assay is a rapid and reliable tool to define MSI status, and it could represent a valuable alternative to conventional MSI-PCR methods.

BackgroundMicrosatellite-stable (MSS) and instability-low (MSI-L) metastatic colorectal cancer (mCRC) are typically characterised as ”immune-excluded/desert” tumour microenvironments lacking T-cell infiltration. Anti-PD-1 monotherapy has little clinical benefit in MSS/MSI-L mCRC1 and knowledge of the effects of PD-1 inhibition on T-cell activation/infiltration in this population is limited. Novel combination therapies to overcome anti-PD-1 resistance are required. SPICE is a multicentre, open-label, phase 1 study of the tumour-selective chimeric Ad11/Ad3 group B oncolytic adenovirus enadenotucirev plus nivolumab in patients with metastatic/advanced epithelial tumours refractory to standard therapy. Preliminary data from patients with MSS/MSI-L mCRC demonstrated a median overall survival of 14 months, manageable tolerability and intratumoural T-cell infiltration.2 Here we characterise the immunological effects of tumour re-engineering with enadenotucirev in combination with nivolumab in patients with MSS/MSI-L mCRC.MethodsPatients received increasing doses and/or cycles of intravenous enadenotucirev followed by up to 8 cycles of nivolumab as previously described.2 Wherever possible, pre- and post-treatment (~5 weeks post-first enadenotucirev) biopsies were collected; samples were analysed using immunohistochemistry and automated image analysis. Peripheral blood mononuclear cell immunophenotyping (multiparameter flow cytometry) and serum cytokines were assessed at multiple times.Results43 patients with mCRC were treated (86% MSS/MSI-L; 14% unknown). Among the 13 patients (12/13 MSS/MSI-L; 1/13 unknown) with matched biopsies, 11 had increased intratumoural and stromal CD8+ T-cell infiltration in post-treatment biopsies (median [Q1-Q3] fold changes 6.5× [1.5–25.4] and 1.9× [1.5–3.9], respectively; figure 1). CD4+ T-cell density increased in 10/13 patients and 8/13 patients had increased proportions of PD-L1+ immune cells. Increases in CD8 T-cell proliferation (Ki67; 7/9 patients) and cytolytic activity (Granzyme B; 7/13 patients) markers were seen. 4/13 patients converted from a ”desert” to an ”inflamed” immune phenotype (pathologist scored CD8/pan-cytokeratin staining). Immunophenotyping showed trends towards increased T-cell activation (CD38+ and HLA-DR+ CD8+ T cell populations) post-treatment (9/10 patients), including in one patient who had only received enadenotucirev prior to sampling. Persistent increases in inflammatory cytokines (IFNγ, IL-12p70, IL-17a) were seen in two patients from ~Day 15, including one who achieved a sustained objective response.Abstract 342 Figure 1Tumour immune cell infiltration following treatment with enadenotucirev plus nivolumabConclusionsThese data show that intravenous enadenotucirev plus nivolumab can induce immune infiltration/activation within MSS/MSI-L mCRC. These encouraging findings suggest that immune activation can be achieved even in ”immune-excluded/desert” tumours. SPICE has been closed following completion of dose-escalation. Efforts are now focused on the development of next-generation variants of enadenotucirev designed to further re-programme the tumour microenvironment by expressing immune-enhancer transgenes (T-SIGn vectors); these studies are ongoing (NCT04830592, NCT04053283, NCT03852511).AcknowledgementsThis study was funded by PsiOxus Therapeutics Limited and Bristol Myers Squibb. Medical writing support: Lola Parfitt, MRes, of PsiOxus Therapeutics Limited.Trial RegistrationEudraCT number2017-001231-39NCT number: NCT02636036ReferencesKawazoe A, Kuboki Y, Shinozaki E, et al. Multicenter phase I/II trial of napabucasin and pembrolizumab in patients with metastatic colorectal cancer (EPOC1503/SCOOP trial). Clin Cancer Res 2020;26:5887–5894.Fakih M, Wang D, Harb W, et al. SPICE: a phase I multicenter study of enadenotucirev in combination with nivolumab in tumors of epithelial origin: an analysis of the metastatic colorectal cancer patients in the dose escalation phase. Ann Oncol 2019:30(suppl_5):v252.Ethics ApprovalThe study was approved by the WCG Institutional Review Board (study approval number 20152656), UCLA Institutional Review Board (study approval number IRB#15-002010), Vanderbilt Institutional Review Board (study approval number IRB #171453) and Henry Ford Institutional Review Board (study approval number IRB #10349).

Objective To determine the cost-effectiveness of lenvatinib plus pembrolizumab (LP) in patients with microsatellite stable (MSS), recurrent, pretreated endometrial cancer (EC). Methods A decision analysis model was created to evaluate the cost-effectiveness of LP relative to doxorubicin, pegylated liposomal doxorubicin (PLD), and bevacizumab in patients with recurrent pretreated MSS EC. Published data was used to estimate quality adjusted life years (QALYs) and drug cost estimates were obtained using average wholesale prices. A health state utility (HSU) penalty of −0.10 was applied to the LP group to account for treatment toxicity. Incremental cost-effectiveness ratios (ICERs) were calculated to determine cost/QALY. The willingness to pay threshold (WTP) was set at $100,000 per QALY saved. Sensitivity analyses were performed on cost, effectiveness, and HSU penalty for LP. Results Costs of treatment with doxorubicin, PLD, and bevacizumab are $23.7 million (M), $56.9 M, and $250.8 M respectively. Cost of treatment with LP is $1.8 billion. Relative to doxorubicin, the ICERs for PLD, bevacizumab, and LP are $56,808, $345,824, and $1.6 M respectively. A sensitivity analysis varying the cost of LP shows that if the combined drug cost decreases from over $58,000 to less than $11,000 per cycle, this strategy would be cost-effective. Eliminating the HSU penalty for LP decreased the ICER $1.0 M while increasing the penalty to −0.20 increased the ICER to $3.7 M. Conclusions LP is not cost-effective in patients with recurrent pretreated, MSS EC. A dramatic reduction in cost of LP is required for this novel strategy to be cost-effective.

Background/aim The majority of colorectal cancer (CRC) cases, which are microsatellite stable (MSS) and do not harbor mismatch repair deficiency/microsatellite instability, are resistant to immunotherapy. Identification of patients with exceptional responses in MSS CRC and predictive biomarkers is an unmet need that needs to be addressed. Case report We report three cases of MSS CRC with durable clinical benefit from immunotherapy with anti-PD-1 checkpoint inhibitors. Two cases bear a POLE P286R mutation, which has been associated with lack of immunotherapy response in MSS CRC. Two cases bear alterations in Ataxia-Telangiectasia Mutated (ATM) which may contribute to observed responses, including interaction with a co-administered intratumoral stimulator of interferon genes (STING) pathway agonist in one patient. Conclusion Novel DNA damage repair alterations, including mutations in ATM, can provide insight into additional mechanisms by which genomic alterations can sensitize MSS CRC to diverse immunotherapies.

Immune checkpoint inhibition (ICI) has transformed the management of metastatic colorectal cancer (mCRC) with mismatch-repair deficiency (dMMR) and microsatellite instability (MSI-H), though this constitutes on average less than 5% of mCRC, and ICI is ineffective in preserved MMR/microsatellite stable disease (pMMR/MSS). Here we review the efficacy of ICI in dMMR/MSI-H mCRC, poor response to ICI in pMMR/MSS mCRC, role for ICI in locally advanced disease, biomarkers of response, novel immunotherapies, and future directions in targeting resistance mechanisms.

Purpose: Colorectal cancer (CRC) incidence is increasing in adults younger than 50 years. This study evaluated clinicopathological characteristics and outcome of adolescent and young adult (AYA)-on...

Most colorectal cancers are microsatellite-stable with no response to anti-PD-1 therapy, necessitating the development of new immunomodulatory treatment strategies. Coinhibition of anti-PD-1 and STAT3 can elicit an effective antitumor response in a small subset of patients with microsatellite-stable colorectal cancer, and biomarkers predictive of response are under investigation. See related article by Kawazoe et al., p. 5887

Background: Microsatellite-stable (MSS) colon adenocarcinoma (COAD) patients are not sensitive to immune checkpoint inhibitors. Here, we focused on analyzing the relationship between homologous recombination repair (HRR)-related gene mutations and clinical immunotherapy responses in MSS COAD. Methods: The mutational landscape was profiled in a cohort of 406 Chinese COAD patients via next-generation sequencing (NGS). Correlations between HRR gene mutations and tumor immunity or clinical outcomes in two COAD genomic datasets were analyzed via bioinformatics. Results: In the Chinese cohort, seventy (17%) patients exhibited genomic alterations in HRR genes; ATM (9%), BRCA2 (4%), ATR (3%), RAD50 (3%) and BRIP1 (3%) were the most frequently mutated. In the MSK-IMPACT COAD cohort (immune checkpoint inhibitor-treated), HRR-mut patients (n=34) survived longer than HRR-wt patients (n=50) (log-rank P < 0.01). Based on the TCGA MSS COAD cohort, HRR gene mutations increased immune activities, such as infiltration of cytotoxic cells (P < 0.05) and exhausted CD8+ T cells (P < 0.01), and increased the IFN-γ scores (P < 0.05). The results differed in MSI-H COAD patients (all P > 0.05). Conclusion: HRR gene mutations significantly increased immune activities in MSS COAD patients, implying the feasibility of the HRR-mut status as an immunotherapy response predictor in MSS COAD.

Key Points Question Can combined immune checkpoint inhibition improve overall survival (OS) in patients with advanced refractory colorectal cancer (CRC)? Findings In this randomized phase 2 study with 180 patients randomized in a 2:1 ratio to tremelimumab and durvalumab plus best supportive care or best supportive care alone, the median OS was 6.6 months for durvalumab and tremelimumab and 4.1 months for best supportive care; correlative analysis revealed that patients with plasma tumor mutation burden (TMB) of 28 or more variants per megabase had the greatest OS benefit. Meaning Combined immune checkpoint inhibition may prolong OS in patients with advanced refractory CRC., This phase 2 randomized clinical trial evaluates the outcomes of combined immune checkpoint inhibition plus best supportive care vs best supportive care alone for patients with advanced colorectal cancer., Importance Single-agent immune checkpoint inhibition has not shown activities in advanced refractory colorectal cancer (CRC), other than in those patients who are microsatellite-instability high (MSI-H). Objective To evaluate whether combining programmed death-ligand 1 (PD-L1) and cytotoxic T-lymphocyte–associated protein 4 (CTLA-4) inhibition improved patient survival in metastatic refractory CRC. Design, Setting, and Participants A randomized phase 2 study was conducted in 27 cancer centers across Canada between August 2016 and June 2017, and data were analyzed on October 18, 2018. Eligible patients had histologically confirmed adenocarcinoma of the colon or rectum; received all available standard systemic therapies (fluoropyrimidines, oxaliplatin, irinotecan, and bevacizumab if appropriate; cetuximab or panitumumab if RAS wild-type tumors; regorafenib if available); were aged 18 years or older; had adequate organ function; had Eastern Cooperative Oncology Group performance status of 0 or 1, and measurable disease. Interventions We randomly assigned patients to receive either 75 mg of tremelimumab every 28 days for the first 4 cycles plus 1500 mg durvalumab every 28 days, or best supportive care alone (BSC) in a 2:1 ratio. Main Outcomes and Measures The primary end point was overall survival (OS) and a 2-sided P

In an integrated genomic and clinical analysis, we evaluate the effects of Wnt and DNA damage response pathway alterations on metastatic colorectal cancer.

Summary Purpose This study aims to analyze sensitivities and polymorphisms of the Bethesda panel markers (BAT25, BAT26, D2S123, D5S346 and D17S250) for microsatellite instability testing in Chinese from Jiangsu Province and their clinical implication. Methods MSI, sensitivity and polymorphism analysis in 541 colorectal cancer (CRC) patients were detected by fragment analysis. Results Five hundred and twenty-five tissue samples and 541 blood samples of the 541 sample pairs were successfully amplified. Thirty-four (6.5%) cases were MSI-high (MSI-H) while 33 (6.3%) and 458 (87.2%) were MSI-low (MSI-L) and microsatellite stable (MSS), respectively. BAT26 (85.3%) exhibited the highest instability followed by BAT25 (82.4%), D2S123 (67.6%), D17S250 (64.7%) and D5S346 (50.0%) in MSI-H cases. The median ages of CRC patients with LS, MSI-H, MSI-L and MSS status were 38–43, 48, 60 and 63, respectively. 75.0%, 44.1%, 12.1% and 7.0% CRC cases were mucinous carcinomas in LS, MSI-H, MSI-L and MSS group, respectively. For D2S123, D17S250 and D5S346, heterozygosity was 80.8%, 74.1% and 57.7% and sizes of polymorphic variation range (PVR) were 207 bp to 234 bp, 140 bp to 169 bp and 109 bp to 137 bp, respectively. For D2S123 and D5S346, there was a bimodal distribution distinguishing the D17S250 from an indistinct trimodal or tetramodal distribution. Conclusion MSI-H cases showed earlier onset and higher proportion of mucinous carcinomas. Mononucleotide BAT26 and BAT25 exhibited higher sensitivity than dinucleotides D2S123, D17S250 and D5S346 in the Chinese population. The dinucleotide markers were highly polymorphic with high percent of heterozygosity, great variation in repeat length and non-normal distribution in Chinese population from Jiangsu Province.

Tumor mutational burden correlates with response to immune checkpoint blockade in multiple solid tumors, though in microsatellite stable tumors this association is weak and of limited clinical utility. Here, we uniformly analyzed whole exome sequencing (WES) of 249 tumors and matched normal tissue from patients with clinically annotated outcomes to immune checkpoint therapy, including radiographic response, across multiple cancer types to examine additional tumor genomic features that contribute to selective response. Our analyses identified genomic correlates of response beyond mutational burden, including somatic events in individual driver genes, certain global mutational signatures, and specific HLA-restricted neoantigens. However, these features were often inter-related, highlighting the complexity of identifying genetic driver events that generate an immunoresponsive tumor environment. This study lays a path forward in analyzing large clinical cohorts in an integrated and multifaceted manner to enhance our ability to discover clinically meaningful predictive features of response to immune checkpoint blockade.

BackgroundColon cancer (CRC) is the second leading cause of cancer-related deaths in the US. CRC incidence is on the rise and there is an alarming increase in young onset CRC cases. Immune checkpoint inhibitors (ICIs) have yielded promising anti-tumor results in microsatellite instable high (MSI-high) patients, which represent only 15% of tumors. The remaining 85% are denoted as microsatellite stable (MSS) and are unresponsive to ICI. Using a murine glioma model, our group has previously found the combination of anti-PD-1 and a transfer of hematopoietic stem cells (HSCs) can sensitize mice that are resistant to anti-PD-1 alone. We evaluated survival after treatment with this combinatorial platform 3 or 5 days post-implantation in subcutaneous CRC-bearing mice and also phenotyped the splenic compartment of mice at endpoint.Methods1x106 MSS CRC cells, CT26, were subcutaneously injected into the right flank of BALB/cJ mice. 3 or 5 days later, HSCs were isolated from naïve BALB/cJ mice and injected through the tail vein into CT26-bearing mice and were also given 10 mg/kg anti-PD-1. Mice were given 3 additional doses of anti-PD-1 for a total of doses either every 3 or 5 days. Mice were sacrificed when tumors reached 1.5 cm at its widest point and spleens were excised and stained for flow cytometry.ResultsWhen mice were treated with HSC/anti-PD-1 3 days post-tumor implantation, we observed a statistically significant increase in survival in mice that received combinatorial HSCs and anti-PD-1 relative to no treatment control mice (p=0.0034, Mantel-Cox long-rank test) as well as mice that received HSCs alone (p=0.0462, Mantel-Cox log-rank test. In the same 3 day cohort, no differences in the frequency of T cell populations were observed. However, we found mice that received this combination therapy had a significant increase in the frequency of splenic CD11c+ MHC II+ dendritic cells (DCs) relative to no treatment control mice (p=0.0364, Mann-Whitney t test). When mice were treated with HSC/anti-PD-1 5 days post-tumor implantation, we found a statistically significant increase in survival of mice treated with combinatorial HSCs and anti-PD-1 compared to no treatment control mice (p=0.0024, Mantel-Cox log-rank test) and relative to mice that received HSC monotherapy (p=0.0462, Mantel-Cox log-rank test).ConclusionsThese results suggest combinatorial HSCs and anti-PD-1 represents a promising therapeutic axis in a murine model of MSS CRC. In addition, the increase in splenic DCs suggests the mechanism behind this anti-tumor response may be expansion of DCs within the periphery.Ethics ApprovalAll animal work approved through University of Florida IACUC # 201910777

Approximately 20% early-stage (I/II) colorectal cancer (CRC) patients develop metastases despite curative surgery. We aim to develop a formalin-fixed and paraffin-embedded (FFPE)-based predictor of metastases in early-stage, clinically-defined low risk, microsatellite-stable (MSS) CRC patients. We considered genome-wide mRNA and miRNA expression and mutation status of 20 genes assayed in 150 fresh-frozen tumours with known metastasis status. We selected 193 genes for further analysis using NanoString nCounter arrays on corresponding FFPE tumours. Neither mutation status nor miRNA expression improved the estimated prediction. The final predictor, ColoMet19, based on the top 19 genes' mRNA levels trained by Random Forest machine-learning strategy, had an estimated positive-predictive-value (PPV) of 0.66. We tested ColoMet19 on an independent test-set of 131 tumours and obtained a population-adjusted PPV of 0.67 indicating that early-stage CRC patients who tested positive have a 67% risk of developing metastases, substantially higher than the metastasis risk of 40% for node-positive (Stage III) patients who are generally treated with chemotherapy. Predicted-positive patients also had poorer metastasis-free survival (hazard ratios [HR] = 1.92, design-set; HR = 2.05, test-set). Thus, early-stage CRC patients who test positive may be considered for adjuvant therapy after surgery.

ZusammenfassungEine Meningeosis neoplastica ist eine seltene, aber schwerwiegende Komplikation solider Neopasien (Melanome, Mamma-, Bronchial- oder gastrointestinale Karzinome). Die klinische Manifestation der Meningeosis ist äußerst variabel. Sie äußert sich z. B. in radikulären Schmerzen mit oder ohne neurologischen Ausfällen sowie in Kopfschmerzen bis hin zu halluzinatorischen Reizsymptomen. Ob dieses unspezifischen Symptomcharakters wird eine Meningeosis neoplastica häufig zu spät diagnostiziert und behandelt. Wir berichten hier über den seltenen Fall einer Patientin mit einem lymphatisch und ossär metastasierten BRAF-mutierten Mikrosatelliten-stabilen Kolonkarzinom, welche einen Monat nach der Diagnosestellung neurologische Reiz- und Ausfallsymptome entwickelte. Durch den zytologischen Nachweis von Tumorzellen im Liquorsediment konnte – trotz einer unauffälligen MRT-Diagnostik – eine Meningeosis carcinomatosa gesichert werden. Unter einer intrathekalen Therapie mit Methotrexat, kombiniert mit einer intensiven systemischen Antikörperchemotherapie, wurde passager eine gute partielle Remission der Tumorerkrankung erreicht. Ca. 8 Monate nach Therapiebeginn entwickelte jedoch die Patientin eine progrediente Meningeosis und verstarb wenige Wochen später.

The prognostic value of CpG island methylator phenotype (CIMP) in colorectal cancer remains unsettled. We aimed to assess the prognostic value of this phenotype analyzing a total of 1126 tumor samples obtained from two Norwegian consecutive colorectal cancer series. CIMP status was determined by analyzing the 5-markers CAGNA1G, IGF2, NEUROG1, RUNX3 and SOCS1 by quantitative methylation specific PCR (qMSP). The effect of CIMP on time to recurrence (TTR) and overall survival (OS) were determined by uni- and multivariate analyses. Subgroup analyses were conducted according to MSI and BRAF mutation status, disease stage, and also age at time of diagnosis (

Background: Grade 3 (G3, poorly differentiated) is an important treatment-decision factor in stage II colon cancer, but no unified diagnostic criteria are established. According to previous studies, an intra-tumoural poorly differentiated area with no glandular formation (POR) that fills the microscopic field of a 40× objective lens was an essential factor that defined G3. We aimed to prospectively validate this in a randomised controlled study of adjuvant chemotherapy (SACURA trial). Methods: Between 2006 and 2010, we enrolled 991 patients with stage II colon cancer from 123 institutions. POR was quantitatively graded according to the 40× objective lens rule and the intensity of poorly differentiated clusters (GradePOR). The prognostic power of GradePOR was compared with that of the conventional tumour grade based on the predominant histology rule (Gradeconv). Findings: According to GradePOR, 313, 526 and 152 tumours were classified as G1POR, G2POR and G3POR, respectively, and the 5-year relapse-free survival (RFS) rates were 91·1%, 82·9%, and 74·7%, respectively (P < 0·0001). When G3POR and G3conv were alternatively added to the standard prognostic model consisting of eight conventional factors, only G3POR was a significant factor for RFS (P = 0·040, Wald test). The adverse impact of G3POR on RFS was greater in the microsatellite stable (MSS)/microsatellite instability (MSI)-low subset (hazard ratio [HR], 2·61; 95% confidence interval [CI], 1·81–3·77) compared with that in the full analysis set (HR, 1·93; 95% CI, 1·34–2·77). In the MSS/MSI-low subset, the 5-year RFS rate of patients with G3POR tumours in the adjuvant chemotherapy group achieved greater improvement (9·1%) than the surgery-alone group (HR, 0·65; 95% CI, 0·34–1·24). Interpretation: The validated prognostic value of the least differentiation policy with the 40× objective lens rule may be highlighted as the diagnostic criterion for G3 in the adjuvant treatment setting for stage II colon cancer, particularly for MSS/MSI-low tumours. Trial Registration: ClinicalTrials.gov NCT00392899 Funding: This study was supported by the Foundation for Biomedical Research and Innovation at Kobe, Translational Research Center for Medical Innovation (TRI), under the funding contract with Taiho Pharmaceutical Co. Ltd., Japan. Declaration of Interests: MI has received consulting fees from Taiho Pharmaceutical Co. Ltd., BristolMyers Squibb and Merck Serono Co. Ltd; honoraria from Taiho, Chugai Pharmaceutical Co. Ltd., and Yakult Honsha Co. Ltd. HM has received consulting fees from Otsuka Pharmaceutical Factory, Inc. and Sysmex Co.; honoraria from Taiho, Chugai, Yakult Honsha, Daiichi Sankyo Co. Ltd., Astellas Pharma Inc. NT has received research funding from Taiho, Chugai, and Yakult Honsha; honoraria from Taiho, Chugai, Takeda Pharmaceutical Co. Ltd., Merck Serono. YS has received honoraria from Taiho, Chugai and Yakult Honsha. KT has received honoraria from Taiho and Takeda. KK has received consulting fees from Taiho and Chugai; honoraria from Taiho, Chugai, Bristol-Myers, Merck Serono and Otsuka. MW has received research funding from Taiho, Chugai, Yakult Honsha, Johnson and Johnson K. K. and Covidien Japan Co. Ltd. YK has received honoraria from Taiho and Chugai. H. Ueno has received honoraria from Taiho, Chugai, Yakult Honsha, BristolMyers and Daiichi Sankyo. TI has received research funding from Taiho; honoraria from Chugai. H. Uetake has received consulting fees, research funding, and honoraria from Taiho, Chugai, Takeda, Bristol-Myers and Merck Serono. SM has no competing interest. ST has received consulting fees from Taiho, Daiichi Sankyo and Solasia Pharma K. K.; research funding from Daiichi Sankyo, Yakult Honsha and Kureha Co. Ltd.; honoraria from Daiichi Sankyo. KS has received consultant fees, research funding and honoraria from Taiho, Chugai, Takeda, Yakult Honsha, Daiichi Sankyo, Bristol-Myers, Merck Serono, and Pfizer Co. Ltd. Ethics Approval Statement: The study protocol was approved by the Institutional Review Boards of each participating institution and was conducted in accordance with the tenets of the Declaration of Helsinki and comparable Japanese ethical standards. Furthermore, written informed consent was obtained from all study participants.

Programmed death 1 (PD-1)-targeted therapy has benefited patients with microsatellite instability-high metastatic colorectal cancer (mCRC). However, the efficacy of PD-1-targeted therapy is poor in patients with microsatellite-stable (MSS) mCRC. Therefore, it is imperative to explore additional co-inhibitory molecular signalling pathways to improve the efficacy of immunotherapy in MSS mCRC treatment. In the present study, the association between cyclin-dependent kinase 9 (CDK9) expression and the survival of patients with CRC was analysed using RNA sequencing data from 605 patients, including 121 cases of mortality, from human cancer datasets. Furthermore, 35 clinical MSS stage III–IV CRC specimens were collected to assess CDK9 protein expression by immunohistochemistry, and the frequency of tumor-infiltrating CD8+ T cells was assessed by flow cytometry. The human cancer datasets demonstrated that upregulation CDK9 significantly shortened the survival of patients with stage II–IV colon cancer. Additionally, CDK9 mRNA expression was positively correlated with the expression levels of genes associated with immune evasion in the tumor. Notably, CDK9 was expression was upregulated in stage IV CRC compared with para-cancerous tissues and early-stage tumors. Interestingly, CDK9 expression was negatively associated with the infiltration of CD8+ T cells at the tumor site. In addition, the expression levels of T-cell immunoglobulin mucin family member 3 and CD39, proteins associated with exhaustion, on tumor-infiltrating CD8+ T cells were significantly elevated in patients with abnormal CDK9 expression levels. The present study demonstrated that CDK9 expression was negatively associated with CD8+ T cell infiltration and positively associated with CD8+ T cell exhaustion in MSS mCRC. In conclusion, CDK9 may be utilized to evaluate the prognosis and the immune-type of the tumor microenvironment in patients with MSS mCRC.

Recent research has established tumor budding as a prognostic factor and a possible histomorphologic reflection of epithelial-mesenchymal transition in colorectal cancer, highlighting the ability of cancer cells exhibiting epithelial-mesenchymal transition to resist chemotherapy.This study aimed to investigate the clinical benefits of adjuvant chemotherapy according to the tumor budding status in microsatellite-stable stage III colorectal cancer.This was a retrospective study of 2 cohorts.The study was conducted at the National Defense Medical College in Japan.We reviewed 2 data sets of patients with microsatellite-stable stage III colorectal cancer with curatively intended surgery (R0) from 1999 to 2005 (first cohort; n = 203) and 2006 to 2012 (second cohort; n = 346). In both cohorts, 128 and 203 patients received 5-fluorouracil-based adjuvant chemotherapy and 75 and 143 patients did not.We assessed the benefits of adjuvant chemotherapy according to the grades of tumor budding based on the cancer-specific survival.In low-budding tumors, the chemotherapy group exhibited better cancer-specific survival than the surgery-alone group (first cohort, 93.1% vs 65.5%, p = 0.001; second cohort, 94.0% vs 76.0%, p0.0001). Conversely, the prognostic difference between the chemotherapy and surgery-alone groups was statistically insignificant in high-budding tumors (first cohort, 59.7% vs 52.4%, p = 0.57; second cohort, 83.1% vs 75.6%, p = 0.19). The multivariate analysis corroborated the benefits of adjuvant chemotherapy in low-budding tumors (first cohort, p = 0.002, HR = 0.28; second cohort, p0.0001, HR = 0.23) but not in high-budding tumors.Postoperative adjuvant chemotherapy and treatments for recurrence were not homogeneous, and the patient backgrounds differed between the chemotherapy and surgery alone groups.The high-budding group demonstrated resistance to 5-fluorouracil-based chemotherapy, whereas the low-budding group exhibited significant survival benefits from adjuvant chemotherapy in stage III colorectal cancer. See Video Abstract at http://links.lww.com/DCR/B14. BENEFICIOS DE SUPERVIVENCIA DIFERENCIAL DE LA QUIMIOTERAPIA ADYUVANTE BASADA EN 5-FLUOROURACILO PARA PACIENTES CON CÁNCER COLORRECTAL EN ESTADIO III ESTABLE CON MICROSATÉLITE SEGÚN EL ESTADO DE BROTACIÓN DEL TUMOR: UN ANÁLISIS RETROSPECTIVO:: Investigaciones recientes han establecido la aparición de tumores como un factor pronóstico y una posible reflexión histomorfológica de la transición epitelial-mesenquimatosa en el cáncer colorrectal, destacando la capacidad de las células cancerosas que presentan una transición epitelio-mesenquimática para resistir la quimioterapia.El objetivo de este estudio es investigar los beneficios clínicos de la quimioterapia adyuvante según el estado de brotación del tumor en el cáncer colorrectal en estadio III estable con microsatélite.Este fue un estudio retrospectivo de dos cohortes.El estudio se realizó en la Escuela de Medicina de la Defensa Nacional de Japón.Revisamos dos conjuntos de datos de pacientes con cáncer colorrectal en estadio III estable con microsatélite con cirugía de intención curativa (R0) de 1999 a 2005 (primera cohorte; n = 203) y 2006 a 2012 (segunda cohorte; n = 346). En ambas cohortes, 128 y 203 pacientes recibieron quimioterapia adyuvante basada en 5-fluorouracilo y 75 y 143 pacientes no, respectivamente.Evaluamos los beneficios de la quimioterapia adyuvante de acuerdo con los grados de brotación del tumor en función de la supervivencia específica del cáncer.n los tumores con brotes bajos, el grupo de quimioterapia mostró una mejor supervivencia específica al cáncer que el grupo con cirugía sola (primera cohorte, 93.1% vs. 65.5%, p = 0.001; segunda cohorte, 94.0% vs. 76.0%, p0.0001). A la inversa, la diferencia pronóstica entre los grupos de quimioterapia y cirugía sola fue estadísticamente insignificante en los tumores de brotes elevados (primera cohorte, 59.7% vs. 52.4%, p = 0.57; segunda cohorte, 83.1% vs. 75.6%, p = 0.19). El análisis multivariado corroboró los beneficios de la quimioterapia adyuvante en los tumores de brotes bajos (primera cohorte, p = 0,002, índice de riesgo: 0,28; segundo cohorte, p0,0001, índice de riesgo: 0,23) pero no en los tumores de alto brote.a quimioterapia adyuvante postoperatoria y los tratamientos para la recurrencia no fueron homogéneos, y los antecedentes de los pacientes difirieron entre los grupos de quimioterapia y cirugía sola.El grupo de alto brote demostró resistencia a la quimioterapia basada en 5-fluorouracilo, mientras que el grupo de bajo brote mostró beneficios significativos de supervivencia de la quimioterapia adyuvante en el cáncer colorrectal en estadio III. Vea el Resumen del Video en http://links.lww.com/DCR/B14.

Immunotherapy using checkpoint inhibitor targeting PD-1 and PD-L1 revolutionized the treatment of microsatellite instable metastatic colon cancer. Such treatment is now a standard of care for these patients. However, when used as monotherapy checkpoint inhibitors targeting PD-1 and PD-L1 are not effective in metastatic colorectal cancer patients with microsatellite stable tumors. Recent advances in biology provide a rationale for this intrinsic resistance and support the evaluation of combination therapy to reverse resistance. This article will highlight recent findings on the mechanism of intrinsic resistance and recent advances in clinical trials for combination therapy.

3584 Background: Patients (pts) with microsatellite stable (MSS) metastatic colorectal cancer (mCRC) that progressed on ≥2 prior therapies have limited treatment options, with median OS ranging from 6-9 months (mo). In the dose-escalation phase of this first-in-human multicohort study (NCT02720068), the anti-lymphocyte activation gene (LAG)-3 antibody favezelimab (fave) was well tolerated alone and with pembrolizumab (pembro) across all dose levels (Lakhani, SITC, 2018, abstract O26). Here, we evaluate the safety and efficacy of fave alone or in combination with pembro in pts with advanced MSS CRC from the dose confirmation phase. Methods: Eligible pts with MSS PD-1/PD-L1-treatment-naïve mCRC that progressed on prior standard-of-care (3L+) were enrolled (cohort A) to receive the RP2D of 800 mg fave alone (Arm 1), 800 mg fave + 200 mg pembro (Arm 2C), or 800 mg fave + 200 mg pembro (MK-4280A) co-formulation (Arm 5), all Q3W. Treatment continued for 35 cycles or until progression, unacceptable toxicity, or investigator/pt decision. Pts with confirmed progression per irRECIST v1.1 on fave alone could crossover to 800 mg fave + pembro. Safety was assessed in all treated pts; efficacy in the full analysis set (FAS) of all treated pts with baseline scan. Objectives included safety (primary), ORR (RECIST v1.1 by investigator [secondary]), and DOR, PFS, and OS (exploratory). Interim analysis data cut-off was: Oct. 23, 2020. Results: A total of 20 pts received fave (Arm 1); 89 pts (including 9 crossover) received fave + pembro (Arms 2C+5); 12 pts (Arm 1) and 36 pts (Arms 2C+5), had PD-L1 CPS ≥1 tumors. At data cut-off, median follow-up was 5.8 months (mo) in Arm 1 and 6.2 mo in Arms 2C+5. Treatment-related adverse events (TRAEs) were 65% with fave (Arm 1) and 65.2% with fave + pembro (Arms 2C+5). Grade ≥3 TRAEs were 15% (Arm 1), and 20% [Arms 2C+5]). No grade 5 TRAEs were reported. Common TRAEs (≥15%) included fatigue (20.0%), nausea (15%) with fave, and fatigue (16.9%) with fave + pembro. Confirmed ORR was 6.3% (4PR, 1CR) with fave + pembro (Arms 2C+5). No pt receiving fave alone responded. In Arms 2C+5, median DOR was 10.6 mo (range, 5.6-12.7). ORR, OS and PFS by PD-L1 status are reported in the Table. Conclusions: Favezelimab alone or in combination with pembrolizumab had a manageable safety profile, with no treatment-related deaths. Promising antitumor activity was observed with combination therapy, including with MK-4280A, compared with monotherapy most notably in pts with PD-L1 CPS ≥1 tumors. Clinical trial information: NCT02720068. [Table: see text]

e15560 Background: PD-1 blockade is particularly ineffective in patients with microsatellite stable (MSS) or mismatch repair (MMR)-proficient colorectal cancer (CRC). Regorafenib (R) has been shown to modulate anti-tumor immunity through different mechanisms, including the reduction of tumor-associated macrophages (TAMs) and lymphocyte activation or immunosuppressive cells, such as forkhead box P3 (Foxp3)+ CD25+ regulatory T cells (Tregs). Synergy between R and anti–PD-1/PD-L1 antibodies has been demonstrated in pre-clinical models compared to that of either treatment alone. Accordingly, this study attempted to evaluate the combined activity of regorafenib with an immune checkpoint inhibitor. Methods: This trial was a prospective, open-label, monocentric, nonrandomized, single arm study. This study included patients with non MSI-H mCRC who received R (80 mg QD 3weeks/4) and sintilimab (S)(200 mg every 3 weeks).The primary endpoint was the confirmed objective response rate (ORR).The secondary endpoints were progression free survival (PFS),overall survival (OS),disease control rate (DCR) and safety. Results: As of January 8, 2021, 24 patients (median age 59 years) with mCRC were enrolled and received treatment with R+S. RAS wild type was 50% of all patients. In addition, 83.3% of patients received two prior lines of treatment, while 58.3% had liver metastases at enrollment. Of the 24 patients, the best response was observed to be stable disease(SD) in six patients (25%) and progressive disease (PD)in four patients (16.7%). Another nine (37.5%) patients have yet to be evaluated. In the 15 evaluated patients, the ORR(RECIST version 1.1) was 33.3% , the DCR was 73.3%. Additionally, among the 10 evaluated patients with liver metastases, the ORR was 30% , the DCR was 80%. Among the nine evaluated patients with wild-type populations of k-ras, the ORR and DCR was found to be 44.4% and 66.7%, which was higher than the mutation patients. The median PFS was 4.2 (95% CI, 2.5, NA) months, the median OS was not reached. The most common grade 3/4 adverse events were palmar-plantar erythro-dysesthesia syndrome (4.2%), erythra (4.2%). No death was related to the treatment. Moreover, four (16.7%) patients were subject to at least 1 dose modification or treatment interruption. Conclusions: In this study, the combination of R+S achieved a similar ORR with REGONIVO. Furthermore, this combination was well tolerated and had a manageable safety profile. However, due to the limited sample size, some biases may be present. As a result, we will continue to expand the sample size for future verification. Clinical trial information: NCT04745130.