Out of 730 plasma proteins evaluated using MR, genetically elevated levels of five proteins were associated with breast cancer risk, namely CD160, 2’-deoxynucleoside 5’-phosphate N-hydrolase 1 (DNPH1), layilin (LAYN), Leucine rich repeat containing 37 member A2 (LRRC37A2) and toll-like receptor 1 (TLR1), which were confirmed in an independent set of data. This evidence concerns the gene CD160 and breast cancer.