No association between a candidate TCF7L2 variant and risk of breast or ovarian cancer

Two clinic-based case-control studies at the Mayo Clinic were assessed including 798 breast cancer cases, 843 breast cancer controls, 391 ovarian cancer cases, and 458 ovarian cancer controls. Genotyping at TCF7L2 rs12255372 used a 5' endonuclease assay, and statistical analysis used logistic regression among participants as a whole and among a priori-defined subsets.No associations with risk of breast or ovarian cancer were observed (ordinal model, p = 0.62 and p = 0.75, respectively). In addition, no associations were observed among sub-groups defined by age, BMI, family history, stage, grade, histology, or tumor behavior.Although the biology of the Wnt/β-catenin signaling pathway and prior association between rs12255372 and numerous phenotypes warranted examination of this TCF7L2 SNP, no compelling evidence for association with breast or ovarian cancer was observed.Transcription factor 7-like 2 (TCF7L2) encodes a transcription factor involved in Wnt/β-catenin signaling pathway which encompasses an intronic single-nucleotide polymorphism (SNP, rs12255372) that has been associated with risk of Type 2 diabetes in linkage studies and genome-wide association studies [1-4] with potential modification by obesity [5]. TCF7L2 forms an active nuclear complex with β-catenin that binds and induces the expression of target genes involved in cellular proliferation, evasion of apoptosis, and tissue invasion and metastasis. Because of the protein's relevance in this canonical cancer pathway, several cancer association studies have been conducted. Studies report associations with increased risk of familial breast cancer [6] and aggressiveness of prostate cancer [7]; there are conflicting reports in colon cancer showing decreased risk [8], increased risk [9], or differential risk by NSAIDs use [10]. We sought to assess the role of this polymorphism in risk of breast and ovarian cancer and, based on other reports, in subsets defined by body mass index (BMI), family history, and mea