Neoadjuvant chemotherapy used to treat muscle-invasive localized bladder cancer appears to do more than damage cancer cells. The chemo might also harness the immune system to search for and destroy bladder cancer cells, researchers reported at the American Association for Cancer Research annual meeting in Washington.
“The immune system may be an under-recognized contributor to the tumor response to chemotherapy,” according to lead author Philip H. Abbosh, MD, PhD, of Fox Chase Cancer Center, Philadelphia.
Dr. Abbosh and colleagues performed whole exome sequencing and gene expression analyses on three cohorts of patients who had cisplatin-based neoadjuvant chemotherapy.
“We found that tumors with a high mutation burden had a high neoantigen load. Neoantigens are the tumor-associated peptides that can be recognized by the immune system. Responding tumors also had a high CD8 T cell infiltrate signature, suggesting that they were recognizing the neoantigens but were ‘indifferent.’ The last piece of data is very preliminary, but suggests that the PD1 checkpoint may have a role in chemo response. It’s not clear yet if it is a cause or consequence of response, or if it is an epiphenomenon,” Dr. Abbosh told Urology Times.