Piercont F, Rosaria RM, Martini M, et al. - Researchers sought to analyze the expression of PD-L1 both in neoplastic epithelial cells and in stromal inflammatory cells in individuals with a diagnosis of carcinoma in situ (CIS) primary responders and not responders to BCG therapy, in order to verify if the PD-L1 expression could identify patients resistant to BCG treatment. Furthermore, they investigated the same cases the immunoreactivities of anti-PD-L1 MoAbs such as SP263, C23, and SP142. In tumor cells and immune cell compartment, the results have shown that PD-L1 expression is higher in BCG-unresponsive group than in BCG responders, but only the PD-L1 22C3 expression in tumor cells appears to be linked with recurrence of the disease. So, the evidence showed that the PD-L1 22C3 expression could help to distinguish CIS that fails the BCG therapy, supporting the hypothesis that enhanced levels of intratumoral PD-L1 22C3 expressed by the tumor cells may explain the failure of BCG immunotherapy.