So, the BC-causal SNP rs10454142 PPP1R21 and 10 SNPs strongly linked to it are functionally weighty in relation to 11 genes (FOXN2, GTF2A1L, LHCGR, MSH6, RP11-191L17.1, KLRAQ1, RP11-460M2.1, FSHR, PPP1R21, STON1-GTF2A1L, and STON1). This evidence concerns the gene PPP1R21 and breast cancer.