According to the materials of the QTLbase database (accessed 20 August 2023), rs10454142 PPP1R21 and 10 loci in linkage disequilibrium (LD) with it were linked to the level of genome methylation (cg15846641) in the liver (liver hepatocellular carcinoma) (Table S4), and the BC-risk allele C rs10454142 PPP1R21 was associated with hypermethylation of the above DNA site (beta = 0.46 p = 4.31 × 10−9), which may lead to a decrease in gene expression. Here, PPP1R21 is linked to breast cancer.