P2Y12 on platelets plays an important role in the growth of ovarian cancer. (A) Representative images of a necropsy on WT and P2Y12^−/− tumor-bearing mice that carried tumors induced by intraperitoneal injection of ID8-VEGF murine ovarian cancer cells. (B) Mean aggregate tumor weight in WT and P2Y12^−/− tumor-bearing mice (n = 10 mice per group). (C) Proliferation rate as quantified by the percentage of Ki67-positive cells in tumors resected from WT and P2Y12^−/− tumor-bearing mice (n = 15 HPFs/5 mice per group). (D) Apoptosis rate as quantified by CC3 positivity in tumors from WT and P2Y12^−/− mice (n = 15 HPFs/5 mice per group). (E) Representative images of a necropsy on WT and P2Y1^−/− tumor-bearing mice that carried tumors induced by intraperitoneal injection of ID8-VEGF murine ovarian cancer cells. (F) Mean aggregate tumor weight in WT and P2Y1^−/− tumor-bearing mice (n = 10 mice per group). (G) Proliferation rate as quantified by the percentage of Ki67-positive cells in tumors resected from WT and P2Y1^−/− tumor-bearing mice (n = 15 HPFs/5 mice per group). (H) Apoptosis rate as quantified by CC3 positivity in tumors from WT and P2Y1^−/− mice (n = 15 HPFs/5 mice per group). (I) Mean aggregate tumor weight after adoptive transfer of WT hematopoietic progenitor cells to lethally irradiated P2Y12^−/− and WT recipient mice (WT→P2Y12^−/− and WT→WT, respectively). Nontransplanted P2Y12^−/− mice served as a negative control (n = 5 mice per group, P = .0019).