PPP1R21 and breast cancer: We have obtained two five-locus models of SNP interactions of SHBG-related genes showing the most pronounced effect in relation to BC susceptibility (Table 2): rs7910927 JMJD1C-rs3779195 BAIAP2L1-rs10454142 PPP1R21-rs780093 GCKR-rs17496332 PRMT6 (Wald index for risky combinations of this model was the maximum and equals 51.58) and rs8023580 NR2F2-rs7910927 JMJD1C-rs10454142 PPP1R21-rs780093 GCKR-rs17496332 PRMT6 (the Wald index for risky combinations of this model is also the highest and equals 47.77).