PLCD1 and breast cancer: Silence of PLCD1 by promoter CpG methylation has been described in a few epithelial and hematological malignancies, including gastric cancer (GsCa), ESCC, colorectal cancer (CRC), breast cancer (BrCa), pancreatic cancer (PAAD), chronic myeloid leukemia (CML) and non-small cell lung cancer (NSCLC) [10–14].