Assessment of the reliability of MSI status and dMMR proteins deficiency screening on endoscopic biopsy material in esophagus and gastric adenocarcinoma.

BACKGROUND: Microsatellite instability (MSI) is a negative predictive factor for neoadjuvant chemotherapy in resectable oesogastric adenocarcinoma and a crucial determinant for immunotherapy. We aimed to evaluate reliability of dMMR/MSI status screening performed on preoperative endoscopic biopsies. METHODS: Paired pathological samples from biopsies and surgical specimen of oesogastric adenocarcinoma were retrospectively collected between 2009 and 2019. We compared dMMR status obtained by immunohistochemistry (IHC) and MSI status by PCR. dMMR/MSI status on surgical specimen was considered as reference. RESULTS: PCR and IHC were conclusive on biopsies respectively for 53 (96.4%) and 47 (85.5%) of the 55 patients enrolled. IHC was not contributive for 1 surgical specimen. A third reading of IHC was carried out for 3 biopsies. MSI status was observed in 7 (12.5%) surgical specimens. When analyses were contributive, sensitivity and specificity of biopsies for dMMR/MSI were respectively 85% and 98% for PCR vs. 86% and 98% for IHC. Concordance rate between biopsies and surgical specimen was 96.2% for PCR and 97.8% for IHC. CONCLUSIONS: Endoscopic biopsies are a suitable source of tissue for dMMR/MSI status determination in oesogastric adenocarcinoma which should be routinely performed at diagnosis to better adapt neoadjuvant treatment. MINIABSTRACT: By comparison of dMMR phenotype obtained by immunohistochemistry and MSI status by PCR between match-paired samples of oesogastric cancer's endoscopic biopsies and surgical specimen, we observed that biopsies are a suitable source of tissue for dMMR/MSI status determination.

Autologous T cell responses to primary human colorectal cancer spheroids are enhanced by ectonucleotidase inhibition.

OBJECTIVE: T cells are major effectors of the antitumoural immune response. Their activation by tumour-associated antigens can unleash their proliferation and cytotoxic functions, leading to tumour cell elimination. However, tumour-related immunosuppressive mechanisms including the overexpression of immune checkpoints like programmed cell death protein-1 (PD-1), are also engaged, promoting immune escape. Current immunotherapies targeting these pathways have demonstrated weak efficacy in colorectal cancer (CRC). It is thus crucial to find new targets for immunotherapy in this cancer type. DESIGN: In a prospective cohort of patients with CRC, we investigated the phenotype of tumour-related and non-tumour related intestinal T cells (n=44), particularly the adenosinergic pathway, correlating with clinical phenotype. An autologous coculture model was developed between patient-derived primary tumour spheroids and their autologous tumour-associated lymphocytes. We used this relevant model to assess the effects of CD39 blockade on the antitumour T cell response. RESULTS: We show the increased expression of CD39, and its co-expression with PD-1, on tumour infiltrating T cells compared with mucosal lymphocytes. CD39 expression was higher in the right colon and early-stage tumours, thus defining a subset of patients potentially responsive to CD39 blockade. Finally, we demonstrate in autologous conditions that CD39 blockade triggers T cell infiltration and tumour spheroid destruction in cocultures. CONCLUSION: In CRC, CD39 is strongly expressed on tumour infiltrating lymphocytes and its inhibition represents a promising therapeutic strategy for treating patients.

Baveno VI criteria as a prognostic factor for clinical complications in patients with compensated cirrhosis.

BACKGROUND: Combination of liver stiffness measurement and platelets count is a tool to safely rule out varices needing treatment (VNT) in patients with compensated advanced chronic liver disease (cACLD). AIMS: to evaluate 4-year liver-related complications and survival in low-risk patients according to Baveno VI criteria. METHODS: we conducted a monocentric retrospective analysis of prospectively collected data of all consecutive patients, with cirrhosis (LSM≥12.5 kPa) and without previous complication, evaluated between 2012 and 2015. Liver-related complications and survival were compared between 2 groups of patients: favourable (LSM< 20 kPa and platelet count>150.000/mm3) and unfavourable Baveno VI status patients (LSM ≥ 20 kPa or platelet count ≤150.000/mm3). RESULTS: 455 patients with cACLD were analysed. Two hundred patients had favourable Baveno VI criteria, 3.6% with VNT. The 4-year probability of being free of acute decompensation was higher in low-risk patients (94.4 ± 1.8% vs. 85.7%±2.6%, p = 0.018). Unfavourable Baveno status was independently associated with acute decompensation. The probability of being free of HCC was significantly higher in low-risk patients (94.2 ± 1.8% vs. 87.6 ± 2.4%, p = 0.048). Liver-related mortality was not different between the 2 groups (p = 0.56). CONCLUSION: The Baveno VI criteria could predict clinical outcome in cACLD.