PARP6 and breast cancer: 56). On the same line, in breast cancer cells, pharmacological and genetic inhibition of PARP6 caused mitotic defects in breast cancer cells, leading to apoptosis induction (Ref. 57). Differently, PARP6 seems to have an opposite role in gastric cancer, where it promoted cell proliferation, migration and invasion, by activating the survivin pathway (Ref. 58).