Of the SNPs from the PD PRSs, six were significantly associated with breast cancer and were located at five different loci (Table 4): 2q11.2 (in an intron of MAP4K4, mitogen‐activated protein kinase 4), 6p21.32, 16q12.1 (intronic region of CASC16, cancer susceptibility 16), 17q23.2 (in an intron of BRIP1, BRCA1 interacting protein C‐terminal helicase 1) with SNPs associated in the same direction, and 17q21.2 with SNPs inversely associated (in an intron of RETREG3, reticulophagy regulator family member 3). Here, RETREG3 is linked to breast cancer.