According to a new study published in Nature Communications, chemotherapy impairs the capacity of the immune system to recognise pancreatic tumours in patients. Although cancer cells hijack checkpoints to suppress immune responses, the body also detects tumours as abnormal. The research, which was being led by scientists from NYU Langone Health and its Perlmutter Cancer Center, focused on the immune system, especially T cells meant to combat foreign substances like viruses.

In this study, more than 139,000 tumour cells from 27 patients with pancreatic ductal adenocarcinoma (PDAC) were examined. PDAC is a difficult-to-diagnose and treat malignancy, with just 13% of patients surviving more than five years following diagnosis.

One of the novel findings of the study was a threefold reduction in the production of certain inhibitory checkpoint molecules between 11 patients before chemotherapy and six patients after chemotherapy. The study also revealed that TIGIT, a second checkpoint molecule, was the most prevalent inhibitory checkpoint molecule in PDAC and was 18 times more therapeutically targetable than PD1 before chemotherapy but only five times more therapeutically targetable after chemotherapy.

Dr. Aristotelis Tsirigos, PhD, a professor in the Departments of Medicine and Pathology at NYU Grossman School of Medicine and a member of the Perlmutter lab, stated that chemotherapy can have significant effects on the cellular landscape of the tumour microenvironment in pancreatic ductal adenocarcinoma.

Additionally, Dr. Diane Simeone, MD, of the NYU Grossman School of Medicine stated that chemotherapy can make pancreatic ductal adenocarcinomas more resistant to subsequent immunotherapy. However, further research is needed to determine if, as a result of this potential resistance, chemotherapy needs to be combined with immunotherapy at the start of treating this stubborn and often deadly form of cancer.