PTEN and breast cancer: Furthermore, the catalytic mutant of the Cas9 protein, termed dCas9, is effective in facilitating epigenetic changes in several genes associated with cancer, such as Granulin (GRN) in liver cancer, Phosphatase and Tensin Homolog (PTEN) in breast cancer, Suppressor of activator protein 1 (SARI) in colon cancer and Homeobox A11 (HOXA11) in myelogenous leukaemia, resulting in reduced cancer progression22–25.