PCK2 and breast carcinoma: Fourth, while PCK2 silencing impaired survival in ECs, cancer cells display more context-dependence on PCK2 levels: PCK2 overexpression reduced tumorigenesis of liver cancer cells57 and proliferation of renal carcinoma cells58, whereas PCK2 silencing reduced colony formation of human lung cancer cells56 and proliferation of breast cancer cell lines21,59, but PCK2 inhibition enhanced survival of tumor initiating cells of melanoma60, thus illustrating the contextual role of PCK2 in different cell types.