PCNA and breast cancer: Among all the identified genes, SUV39H2 and several other classical oncogenes were prominent: FOXA1 [30, 31], PCNA [32, 33], and EZH2 [34]; additionally, we also found OPTN, which is reported to be involved in the autophagy-related apoptosis of lung cancer cells [35], and STOM, which is a membrane protein whose downregulation indicates poor prognosis and metastasis in non-small cell lung cancer [36] and HER2-positive breast cancer [37] patients.