Swanson, Benjamin

Gastric cancer is a significant global health concern, with CDH1-associated gastric cancer representing a small but important subset of cases. Historically, individuals with CDH1 pathogenic germline variants were advised to undergo prophylactic total gastrectomy due to the high reported risk of gastric cancer and the limited sensitivity of upper endoscopy in detecting signet ring cell carcinoma (SRCC). However, emerging data suggest that the cumulative lifetime risk of advanced gastric cancer among CDH1 germline pathogenic variant carriers is lower than previously thought, and early-stage SRCC detected on endoscopy does not necessarily indicate imminent—or even eventual—progression to advanced cancer. The near-universal presence of T1a SRCC in gastrectomy specimens from asymptomatic CDH1 pathogenic variant carriers calls into question the reflexive recommendation for gastrectomy, including upon detection of SRCC during surveillance. Furthermore, the morbidity and quality-of-life impact associated with total gastrectomy require careful consideration. Active endoscopic surveillance has shown promise as an alternative management strategy for gastrectomy in patients lacking indicators of >T1a SRCC, though current data are limited by short follow-up periods and selection bias. This review synthesizes recent findings on the natural history of CDH1-associated gastric cancer and evaluates the risks and benefits of gastrectomy versus active endoscopic surveillance, with the goal of helping clinicians provide personalized and evidence-based recommendations for patients with CDH1 pathogenic variants.

Multigene panel testing has allowed for the detection of a growing number of inherited pathogenic/likely pathogenic variants in people at high risk of cancer, including endometrial cancer (EC). Hereditary syndromes associated with EC include Lynch syndrome, PTEN hamartoma tumor syndrome, and Peutz-Jeghers syndrome. This manuscript provides the latest recommendations from the NCCN Guidelines for Genetic/Familial High-Risk Assessment: Colorectal, Endometrial, and Gastric on the screening and management of EC in patients at high risk for these syndromes, as well as the advantages and limitations of multigene panel testing. This manuscript also describes recent updates to these guidelines regarding de-implementation of colon cancer screening in individuals with CHEK2 pathogenic/likely pathogenic variants, based on the most up-to-date evidence regarding the association between CHEK2 pathogenic/likely pathogenic variants and colon cancer risk.

Objective Limited efficacy of immune checkpoint inhibitors in pancreatic ductal adenocarcinoma (PDAC) has prompted investigation into combination therapy. We hypothesised that interleukin 6 (IL-6) blockade would modulate immunological features of PDAC and enhance the efficacy of anti-programmed death-1-ligand 1 (PD-L1) checkpoint inhibitor therapy. Design Transcription profiles and IL-6 secretion from primary patient-derived pancreatic stellate cells (PSCs) were analyzed via Nanostring and immunohistochemistry, respectively. In vivo efficacy and mechanistic studies were conducted with antibodies (Abs) targeting IL-6, PD-L1, CD4 or CD8 in subcutaneous or orthotopic models using Panc02, MT5 or KPC-luc cell lines; and the aggressive, genetically engineered PDAC model (Kras LSL−G12D , Trp53 LSL−R270H , Pdx1-cre, Brca2 F/F (KPC-Brca2 mice)). Systemic and local changes in immunophenotype were measured by flow cytometry or immunohistochemical analysis. Results PSCs (n=12) demonstrated prominent IL-6 expression, which was localised to stroma of tumours. Combined IL-6 and PD-L1 blockade elicited efficacy in mice bearing subcutaneous MT5 (p<0.02) and Panc02 tumours (p=0.046), which was accompanied by increased intratumoural effector T lymphocytes (CD62L − CD44 − ). CD8-depleting but not CD4-depleting Abs abrogated the efficacy of combined IL-6 and PD-L1 blockade in mice bearing Panc02 tumours (p=0.0016). This treatment combination also elicited significant antitumour activity in mice bearing orthotopic KPC-luc tumours and limited tumour progression in KPC-Brca2 mice (p<0.001). Histological analysis revealed increased T-cell infiltration and reduced α-smooth muscle actin cells in tumours from multiple models. Finally, IL-6 and PD-L1 blockade increased overall survival in KPC-Brca2 mice compared with isotype controls (p=0.0012). Conclusions These preclinical results indicate that targeted inhibition of IL-6 may enhance the efficacy of anti-PD-L1 in PDAC.