Of the five breast cancer predisposition alleles originally reported by Easton et al. [24], three were shown to be associated with in situ (998 cases of DCIS and LCIS) disease (rs2981582-FGFR2, rs3803662-TOX3, rs889312-MAP3K1) with rs889312 showing a stronger association with DCIS (P-trend 0.007, per allele OR 1.30 for DCIS, per allele OR 1.13 for invasive disease). Here, MAP3K1 is linked to breast carcinoma.