Otherwise, it is reported that MCM2 and MCM4, which have a higher expression in high histological grade breast cancer, may be used as useful parameters to distinguish luminal A and luminal B subtypes instead of ki-67 and are related to poor prognosis (Issac et al., 2019), which is partly consistent with our results in the TNBC subtype. Here, MCM4 is linked to breast carcinoma.