We further analysed pathologic Meta status compared with ER status in primary site tumours and observed that SGSM2 expression correlated only with ER-positive BC patients but not with ER-negative patients (Figure S6(c,d); M1: ER+ vs. ER–, **P = 0.009 and D; M1: ER+ vs. ER–, *P = 0.015). This evidence concerns the gene SGSM2 and breast cancer.