Enhanced antitumor response to immune checkpoint blockade exerted by cisplatin-induced mutagenesis in a murine melanoma model

We report that tumors generated with an in vitro cisplatin-mutagenized YUMM1.7 clone (YUMM1.7-CM) regress in response to immune checkpoint blockade (ICB), while an identical ICB regimen fails to suppress growth of tumors generated with the parental YUMM1.7 cells. Our findings show that in vitro induced cisplatin mutations potentiate the antitumor immune response and ICB efficacy, akin to tumor regression achieved in the parental YUMM1.7 model by ICB administered in conjunction with intratumoral cisplatin injection. Hence, the data uphold the role of tumoral mutation burden in improving immune surveillance and response to ICB, suggesting a path for expanding the range of patients benefiting from ICB therapy.