MACROH2A1 and breast cancer: Artificial over-expression of macroH2A1 reduces the metastatic potential of melanoma and hepatocellular carcinoma (HCC) [14,21,22], whereas small interfering RNA (siRNA)-mediated depletion of macroH2A1 was shown to increase the aggressiveness of HCC, teratoma and breast cancer cells [16,21,23].