BACKGROUND: Serrated lesions and polyps (SP) are precursors of up to 30 % of colorectal cancers (CRC) through the serrated pathway. This often entails early BRAF mutations and MLH1 hypermethylation leading to mismatch repair deficient (dMMR) CRC. We investigated predictors of dMMR CRC among patients with co-occurrence of CRC and SP to increase our knowledge on the serrated pathway.
METHODS: We used data from The Danish Pathology Registry and Danish Colorectal Cancer Groups Database from the period 2010-2021 to investigate risk factors for development of dMMR CRC. We used logistic regression models to identify difference in risk factors of developing dMMR CRC in comparison to CRC with proficient MMR (pMMR).
RESULTS: We included 3273 patients with a median age of 70.7 years [64.3,76.4] of which 1850 (56.5 %) were male. dMMR CRC was present in 592 patients (18.1 %), with loss of MLH1/PMS2 being most common. The risk of dMMR CRC was significantly higher in females OR 3.47 [2.87;4.20]. When adjusting for age, SP subtype, conventional adenomas (CA), anatomical location and lifestyle factors, female sex remained the strongest predictor OR 2.84 [2.27;3.56]. The presence of sessile serrated lesions with or without dysplasia was related to higher risk OR 1.60 [1.11;2.31] and OR 1.42 [1.11;1.82] respectively, while conventional adenomas constituted a lower risk OR 0.68 [0.55;0.84].
CONCLUSIONS: In conclusion we found several predictors of whom female sex had the strongest correlation with dMMR CRC in patients with SP.

BACKGROUND: Most oesophagogastric adenocarcinomas (OGAs) and colorectal cancers (CRCs) are mismatch repair proficient (MMRp), responding poorly to immune checkpoint inhibition. We evaluated the safety and efficacy of domatinostat (histone deacetylase inhibitor) plus avelumab (anti-PD-L1 antibody) in patients with previously treated inoperable, advanced/metastatic MMRp OGA and CRC.
METHODS: Eligible patients were evaluated in a multicentre, open-label dose escalation/dose expansion phase II trial. In the escalation phase, patients received escalating doses of domatinostat [100 mg once daily (OD), 200 mg OD, 200 mg twice daily (BD)] orally for 14 days followed by continuous dosing plus avelumab 10 mg/kg administered intravenously 2-weekly (2qw) to determine the recommended phase II dose (RP2D). The trial expansion phase evaluated the best objective response rate (ORR) during 6 months by RECIST version 1.1 using a Simon two-stage optimal design with 2/9 and 1/10 responses required to proceed to stage 2 in the OGA and CRC cohorts, respectively.
RESULTS: Patients (n = 40) were registered between February 2019 and October 2021. Patients in the dose escalation phase (n = 12) were evaluated to confirm the RP2D of domatinostat 200 mg BD plus avelumab 10 mg/kg. No dose-limiting toxicities were observed. Twenty-one patients were treated at the RP2D, 19 (9 OGA and 10 CRC) were assessable for the best ORR; 2 patients with CRC did not receive combination treatment and were not assessable for the primary endpoint analysis. Six patients were evaluated in the dose escalation and expansion phases. In the OGA cohort, the best ORR was 22.2% (95% one-sided confidence interval lower bound 4.1) and the median duration of disease control was 11.3 months (range 9.9-12.7 months). No responses were observed in the CRC cohort. No treatment-related grade 3-4 adverse events were reported at the RP2D.
CONCLUSIONS: Responses in the OGA cohort met the criteria to expand to stage 2 of recruitment with an acceptable safety profile. There was insufficient signal in the CRC cohort to progress to stage 2.
BACKGROUND: NCT03812796 (registered 23rd January 2019).

Urothelial carcinoma (UC) with deficient mismatch repair (dMMR) is a specific subtype of UC characterized by the loss of mismatch repair (MMR) proteins and its association with Lynch syndrome (LS). However, comprehensive real-world data on the incidence, clinicopathological characteristics, molecular landscape, and biomarker landscape for predicting the efficacy of PD-1/PD-L1 inhibitors in the Chinese patients with dMMR UC remains unknown. We analyzed 374 patients with bladder urothelial carcinoma (BUC) and 232 patients with upper tract urothelial carcinoma (UTUC) using tissue microarrays, immunohistochemistry, and targeted next-generation sequencing. Results showed the incidence of dMMR UC was higher in the upper urinary tract than in the bladder. Genomic analysis identified frequent mutations in KMT2D and KMT2C genes and LS was confirmed in 53.8% of dMMR UC cases. dMMR UC cases displayed microsatellite instability-high (MSI-H) (PCR method) in 91.7% and tumor mutational burden-high (TMB-H) in 40% of cases. The density of intratumoral CD8+ T cells correlated with better overall survival in dMMR UC patients. Positive PD-L1 expression was found in 20% cases, but some patients positively responded to immunotherapy despite negative PD-L1 expression. Our findings provide valuable insights into the characteristics of dMMR UC in the Chinese population and highlights the relevance of genetic testing and immunotherapy biomarkers for treatment decisions.

OBJECTIVE: About 10 to 15% of patients with sporadic colorectal cancer display mutations in DNA mismatch repair (MMR) genes shown as microsatellite instability (MSI). Previous reports of colorectal cancer (CRC) indicate a better prognosis for patients with MSI tumors compared to patients with microsatellite stable (MSS) tumors. In this study, our aim was to investigate whether MSI is an independent prognostic factor in CRC.
METHODS: Patients with stage I-III colorectal cancer and subject to curative surgery during 2002-2006 in the Swedish low-risk colorectal cancer study group cohort were eligible for inclusion. Deficient MMR (dMMR) status was analyzed by immunohistochemistry (IHC) and/or by MSI testing with polymerase chain reaction (PCR). Prognostic follow-up and treatment data were retrieved from patient records. Statistical analyses to assess MSI-status and prognosis were done using logistic regression and survival analyses using the Kaplan-Meier method and Cox regression hazards models adjusted for age, sex, stage, comorbidity, and tumor location.
RESULTS: In total, 463 patients were included, MSI high tumors were present in 66 patients (14%), and the remaining 397 were MSS/MSI low. Within 6 years, distant recurrences were present in 9.1% and 20.2% (P = 0.049), and death occurred in 25.8% and 31.5% in MSI and MSS patients, respectively. There was no statistically significant difference in overall mortality (HR 0.80, 95% CI 0.46-1.38), relapse-free survival (HR 0.82, 95% CI 0.50-1.36), or cancer-specific mortality (HR 1.60, 95% CI 0.73-3.51).
CONCLUSIONS: Despite distant metastases being less common in patients with MSI, there was no association between MSI and overall, relapse-free, or cancer-specific survival.

BACKGROUND: Endometrial carcinoma (EC) is the most common gynecologic malignancy in developed countries and the fourth most frequent in women worldwide. The cornerstone of treatment for EC is surgery. Clinicopathological features are currently used to help determine the individual risk of recurrence and the need for adjuvant treatment after surgery. Nonetheless, there is significant interobserver variability in assigning histologic subtype when using a morphological classification, revealing the need for a more unified approach. The Cancer Genome Atlas (TCGA) project identified 4 distinct prognostic EC subtypes based on genomic abnormalities. Surrogate assays including 3 immunohistochemical markers (p53, MSH6, and PMS2) and 1 molecular test (mutation analysis of the exonuclease domain of DNA polymerase epsilon; POLE) allowed the development and validation of a simplified molecular classifier that correlates with the TCGA classification, has prognostic value, and can easily be used in clinical practice. This molecular classification categorizes EC in 4 subtypes: POLE mutated, mismatch repair-deficient, p53 abnormal, and no specific molecular profile. Applying this classification in clinical practice will help tailor adjuvant treatment decisions.
OBJECTIVE: The aim of this study is to retrospectively apply this novel molecular classification to a cohort of patients with EC treated in a comprehensive cancer center, to assess its applicability in clinical practice, to evaluate clinical outcomes by molecular subtypes, and to assess its prognostic value.
METHODS: In this retrospective cohort study, patients with primary EC diagnosed during and after 2013 and treated or followed at our institution, after definite surgery, will be included. Demographic and clinicopathological data will be obtained from electronic health records and from pathology reports. Laboratory methods will include immunohistochemical study of p53 and mismatch repair proteins, as well as POLE mutational analysis by genetic sequencing. The primary end point is recurrence-free survival and secondary end points are disease-specific survival and overall survival. A descriptive analysis of variables will be carried out. Survival analysis will be performed using the Kaplan-Meier method and the groups will be compared using the log-rank test.
RESULTS: This protocol was reviewed and approved by the Instituto Português de Oncologia do Porto, Portugal, ethics committee in October 2021; patient selection from our cancer registry began the same month. A total of 160 patients will be included. This work will present real-life results that will allow a better understanding of the Portuguese EC population and the distribution of the molecular subgroups throughout. We will use these results to understand the prognostic value of this classification in our population and its role in adjuvant therapy decisions. This study is anticipated to conclude in December 2022.
CONCLUSIONS: This study will provide important information regarding these women\'s outcomes according to this new molecular classification and will support its use when discussing a patient\'s need for adjuvant treatment.
UNASSIGNED: PRR1-10.2196/34461.

The identification of mismatch repair deficient (dMMR) and microsatellite unstable (MSI) endometrial cancers (ECs) is important in screening, diagnosis, and therapeutic stratification of patients. We compared the diagnostic performance of 4 MSI molecular tests based on fragment length assay in capillary electrophoresis (OncoMate™ MSI assay, Promega) and in microcapillary electrophoresis (TapeStation 4200, Agilent); with high-resolution melting (HRM) analysis approaches (Idylla™ MSI Test, Biocartis; EasyPGX® ready MSI, Diatech Pharmacogenetics) on a series of 56 ECs, which was well characterized for MMR status with immunohistochemical approach (IHC, nonmolecular reference test). The concordance of fluorescence capillary electrophoresis with IHC (AUC 0.98) was higher respect to the other molecular methodologies. Otherwise, HRM approaches and microcapillary electrophoresis platform failed to detect MSI-ECs showing minimal microsatellite shifts. In conclusion, in colorectal site, several technologies are eligible for MSI test, whereas in ECs, MSI test should be based on fluorescent capillary electrophoresis as it identifies a higher proportion of cases that could be misdiagnosed with other strategies.

BACKGROUND: To inform effective genomic medicine strategies, it is important to examine current approaches and gaps in well-established applications. Lynch syndrome (LS) causes 3-5% of colorectal cancers (CRCs). While guidelines commonly recommend LS tumour testing of all CRC patients, implementation in health systems is known to be highly variable. To provide insights on the heterogeneity in practice and current bottlenecks in a high-income country with universal healthcare, we characterise the approaches and gaps in LS testing and referral in seven Australian hospitals across three states.
METHODS: We obtained surgery, pathology, and genetics services data for 1,624 patients who underwent CRC resections from 01/01/2017 to 31/12/2018 in the included hospitals.
RESULTS: Tumour testing approaches differed between hospitals, with 0-19% of patients missing mismatch repair deficiency test results (total 211/1,624 patients). Tumour tests to exclude somatic MLH1 loss were incomplete at five hospitals (42/187 patients). Of 74 patients with tumour tests completed appropriately and indicating high risk of LS, 36 (49%) were missing a record of referral to genetics services for diagnostic testing, with higher missingness for older patients (0% of patients aged ≤ 40 years, 76% of patients aged > 70 years). Of 38 patients with high-risk tumour test results and genetics services referral, diagnostic testing was carried out for 25 (89%) and identified a LS pathogenic/likely pathogenic variant for 11 patients (44% of 25; 0.7% of 1,624 patients).
CONCLUSIONS: Given the LS testing and referral gaps, further work is needed to identify strategies for successful integration of LS testing into clinical care, and provide a model for hereditary cancers and broader genomic medicine. Standardised reporting may help clinicians interpret tumour test results and initiate further actions.

The molecular classification system of endometrial carcinoma (EC) in \'The Cancer Genome Atlas\' is widely acknowledged for its prognostic utility. Subsequently, more simplified classification system that incorporate DNA polymerase epsilon (POLE) exonuclease domain mutations, mismatch repair deficiencies (MMRd), and abnormal p53 (P53abn) has also demonstrated its clinical utility. These classifications helped identifying a \'POLE ultramutated\' (POLEmut) category of patients, most of whom show excellent prognoses despite having high-grade ECs. We aimed to investigate the clinicopathological and molecular characteristics of high-grade ECs with POLEmut.
We investigated 414 patients with high-grade ECs (including endometrioid carcinomas grade 3, serous carcinomas, clear cell carcinomas, mixed carcinomas, undifferentiated and dedifferentiated carcinomas, and carcinosarcomas) by sequencing and immunohistochemical staining.
Forty-three tumors (10.4%) were classified as POLEmut, including 2 with new, possibly pathogenic POLE mutations at P286C and L424V. These patients had very good prognoses except for 1 with stage IV disease and residual tumor. Eleven patients in this group also had P53abn and 4 had MMRd; molecular analysis revealed that patients with synchronous POLE pathogenic mutation and other mutations had a POLEmut or MMRd phenotype; survival analysis found no difference in prognosis between these patient categories. The prognoses of patients in the POLEmut EC group were not significantly influenced by treatment or risk category.
Patients with high-grade EC exhibiting POLEmut have very good clinical outcomes, and should be identified urgently in daily work owing to their conflicting morphology. Our findings also provide guidance on subclassifying ECs with poor histological appearance.

OBJECTIVE: Colorectal cancer (CRC) is a heterogeneous disease with distinctive genetic pathways, such as chromosomal instability, microsatellite instability and methylator pathway. Our aim was to correlate clinical and genetic characteristics of CRC patients in order to understand clinical implications of tumour genotype.
METHODS: Single-institution retrospective cohort of patients who underwent curative surgery for CRC, from 2012 to 2014. RAS and BRAF mutations were evaluated with the real-time PCR technique Idylla®. Mismatch repair deficiency (dMMR) was characterized by absence of MLH1, MSH6, MSH2 and/or PMS2 expression, evaluated by tissue microarrays. Overall survival (OS) and disease-free survival (DFS) were assessed using survival analysis.
RESULTS: Overall, 242 patients were included (males 57.4%, age 69.3 ± 12.9 years; median follow-up 49 months). RAS-mutated tumours were associated with reduced DFS (p = 0.02) and OS (p = 0.045) in stage I-III CRC. BRAF-mutated tumours were more predominant in females and in the right colon, similarly to dMMR tumours. BRAF status did not influence OS (4 years)/DFS (3.5 years) in stage I-III disease. However, after relapse, length of survival was 3.5 months in BRAF-mutated tumours in contrast to 18.6 months in BRAF wild-type tumours (p = NS). No germline mutations in mismatch repair genes were so far identified in the patients with dMMR tumours. Molecular phenotype (RAS, BRAF and MMR) did not influence OS in metastatic patients. Our small sample size may be a limitation of the study.
CONCLUSIONS: In our cohort, RAS-mutated tumours were associated with worse DFS and OS in early-stage CRC, whereas the remaining molecular variables had no prognostic influence.
UNASSIGNED: O cancro colo-rectal (CCR) é uma doença heterogénea, com vias genéticas distintas, nomeadamente instabilidade cromossómica, instabilidade de microssatélites e via metiladora. O nosso objetivo foi correlacionar as características clínicas e genéticas dos doentes com CCR e, deste modo, conhecer as implicações na prática clínica do genótipo tumoral.
UNASSIGNED: Estudo de coorte retrospectivo unicêntrico de doentes diagnosticados com CCR e submetidos a cirurgia com intuito curativo, entre 2012 e 2014. As mutações RAS e BRAF foram avaliadas pela técnica de real time PCR Idylla®. A deficiência de mismatch repair (MMR) foi avaliada pela técnica de tissue microarrays e definida pela ausência de expressão de MLH1, MSH6, MSH2 e/ou PMS2. A sobrevivência global (SG) e a sobrevivência livre de doença (SLD) foram avaliadas por análise de sobrevivência.
RESULTS: No total, foram incluídos 242 doentes (homens 57.4%, idade 69.3 ± 12.9 anos, mediana de seguimento de 49 meses). Os tumores RAS-mutados associaram-se a menor SLD (p = 0.02) e SG (p = 0.045) em doentes com CCR estadio I–III. Os tumores BRAF-mutados foram mais frequentes em mulheres e nos tumores do cólon direito, assim como os tumores com deficiência para MMR. O status BRAF não influenciou a SG (4 anos)/SLD (3.5 anos) nos estadio I–III. Contudo, após a recidiva, o tempo de sobrevivência foi de 3.5 meses nos tumores BRAF-mutados, em comparação com 18.6 meses nos tumores sem esta mutação (p = NS). Não se identificaram mutações germinativas nos genes de mismatch repair nos doentes com tumores deficientes para estas proteinas (dMMR). O perfil molecular (RAS, BRAF e MMR) não influenciou a sobrevivência global dos doentes com metástases ao diagnóstico. O tamanho da amostra pode ser uma limitação do estudo.
UNASSIGNED: Na nossa coorte, os tumores RASmutados associaram-se a pior SLD e SG nos estádios precoces de CCR. Os restantes marcadores moleculares não influenciaram o prognóstico dos doentes.

Background: Challenges in identifying microsatellite instability (MSI)/mismatch repair (MMR)-tested colorectal carcinoma (CRC) patients in electronic health records have led to gaps in the understanding of MSI-high/deficient mismatch repair prevalence. Methods: An algorithm to identify MSI-/MMR-tested Veterans Affairs patients was developed and an observational study of adult CRC patients with MSI/MMR testing from 2010 to 2018 was undertaken. Results: An optimized model to identify MSI-/MMR-tested patients yielded high positive predictive value (89.0%) and specificity (97.8%). The authors observed MSI-high/deficient mismatch repair CRC in 54 of 291 patients (18.6%); highest frequencies were observed in stages II (25.9%) and III (22.6%) and lowest in stage IV (5.8%). Conclusions: In this real-world study, the authors proposed a novel method of identifying MSI-/MMR-tested patients. Further validation and refinement of this model, and study in a larger CRC cohort, is warranted.