GZMA and neoplasm: Moreover, the cytotoxic activity was different in the various Th1/Tc1 clones, isolated from the different tumor sites: in fact, the expression of granzyme A was significantly higher in Th1/Tc1 Tcc isolated from HM compared to that released from the tumor tissue counterparts, suggesting that the tumor microenvironment negatively influences the cytolytic activity of T lymphocytes reactive to tumor cells.