The minor allele frequency of Ile655Val (rs1136201)
varies markedly across different populations (from 2%
to 50%). In particular, the valine allele appears to be
more frequent in Europeans, less frequent in Asian
populations and extremely rare in African groups
[14,15]. A caseecontrol study in Chinese women [16]
suggested an increased risk of breast cancer among
carriers of the Val allele; however, a consistent association
has not been demonstrated in meta-analyses