The other common SNP (rs1058808) encodes either
alanine (Ala; GCC) or proline (Pro; CCC) at residue
1170, within a C-terminal, intracellular regulatory
domain [19]. The frequency of the proline allele varies
from more than 50% in Europeans to 10e20% in African
populations [20]. The functional significance of this
SNP is unknown, but two studies in Caucasians with
familial tumours found no influence on breast cancer
risk