PARP1 and malignant colon neoplasm: Recent work from Hottiger ́s group shows that mice with a conditional loss of PARP-1 in myeloid lineages fail to control tumor growth in an MC-38-induced tumor model of colon cancer, which could be attributed to reduced Th1 and CD8+ T cell responses [60], suggesting that PARP-1 in macrophages controls Th1 responses to tumors (Figure 4).