MAP2K1 and breast cancer: The triple interaction of TPH2 rs1386483 and rs1473473 as well as RAF1 rs3729931 increased breast-cancer risk by 20%, a dual interaction of MAPK8 rs10857561 and MAP2K1 rs1347069 by 15%, and MAPK8 rs10857561 alone by 11% (all observed at a prior probability of 0.01).