Ten well-documented breast cancer marker genes were selected [PIP (Urbaniak et al. 2018), SHISA2 (Cheishvili et al. 2015), PDZK1IP1 (Garcia-Heredia et al. 2017), PLEKHS1 (Weinhold et al. 2014), NAT1 (Johansson et al. 2012), TFAP2C (Woodfield et al. 2007), NPNT (Wang et al. 2018a), SCUBE2 (Chen et al. 2018), ASCL2 (Xu et al. 2017), DNAJC1 (Zoppino et al. 2018)], whose expression is expected to correlate strongly with the presence of cancer epithelial cells. The gene discussed is PLEKHS1; the disease is cancer.