SLC6A7 and breast cancer: Among these, 4 SNPs in prot-a-1941, 8 SNPs in prot-a-1944, 10 SNPs in prot-a-203, 14 SNPs in prot-a-2129, and 4 SNPs each in prot-a-2235 and prot-a-641 exhibited strong associations with breast cancer in European populations.