MAP3K1 and breast cancer: One of these studies was published on Nature [4], which identifies trinucleotide-repeat-containing 9 (TNRC9), fibroblast growth factor receptor 2 (FGFR2), mitogen-activated protein kinase 1 (MAP3K1), and leukocyte-specific protein 1 (LSP1) as four novel loci with consistent evidence of association with breast cancer.