MAP3K1 and cancer: Nevertheless, cancer genes tend to expand across large genomic regions [30], and examination of eight genes likely involved in breast cancer through low-penetrance mutations–CASP8, COX11, ESR1, FGFR2, LSP1, MAP3K1, RAD51L1 and TOX3[2]–[6], [13], [14]–showed a trend for larger genomic loci (mean () genomic extension = 211 kilo bases (kb) and standard deviation (σ) = 283 kb; compared to  = 66 kb and σ = 128 kb for all annotated genes in the CGEMS GWAS rank).