P4HA1 and breast cancer: With the same analysis for ER + and ER-BC (Table 2), a nominal significance was observed in the association between ER + BC risk and expressions of P4HA1, SLC12A2, KCNJ11 and PDE1B, among which SLC12A2 and PDE1B were still significant after Bonferroni correction (0.05/(23 × 2) = 1.1 × 10–3).