In addition, nuclear β-catenin in pretreatment-biopsied samples is useful in predicting the efficacy of chemoradiotherapy in patients with rectal cancer.
Using a database of 735 colon and rectal cancers in the Nurse's Health Study and the Health Professionals Follow-up Study, we examined the relationship of tumor SMO expression (assessed by immunohistochemistry) to prognosis, and to clinical, pathological, and tumor molecular features, including mutations of KRAS, BRAF, and PIK3CA, microsatellite instability, CpG island methylator phenotype (CIMP), LINE-1 methylation, and expression of phosphorylated AKT and CTNNB1.
Two US prospective cohort studies (Nurses' Health Study and the Health Professionals Follow-up Study) were used to evaluate CTNNB1 localization by immunohistochemistry in 955 patients with stage I, II, III, or IV colon and rectal cancer from 1980 through 2004.
However, altered expression of beta-catenin and E-cadherin correlated with metastatic disease, and these markers may have prognostic importance in rectal cancer.
No mutation was detected in exon 3 of the CTNNB1 gene and our results thus demonstrate that beta-catenin activation through mutation rarely contributes to the development of sporadic and microsatellite instability stable rectal cancer.
This study concluded that rectal cancer may involve more nuclear beta-catenin in the APC/beta-catenin pathway than colon cancer and/or nuclear beta-catenin may have another role in rectal cancer independently of APC.