WNT signalling pathway in human colorectal carcinoma and adenoma tissues prepared by TMA (Tissue Microarray)

Abstract

Rational: Activation of the Wnt pathway, largely by protein mutations within the pathway itself, leads to increased transcription of genes which play a key role in growth, proliferation, differentiation, apoptosis, genetic stability, migration and angiogenesis. Constitutive activation of Wnt signaling is considered the initial event triggering genesis in most malignant colorectal neoplasias. The identification of cell targets that are potential candidates for more specific modes of cancer treatment hinges on mechanisms of action that can reveal the characteristic patterns of activation of Wnt pathways. Aims: 1. To detect proteins involved in the Wnt signaling pathway in adenomas, colorectal carcinomas, and in healthy colorectal epithelium. 2. To verify the integrity of the canonical and non-canonical Wnt pathway in these same tissues. Method: The study groups will comprise 60 patients with colorectal carcinoma, 40 patients with colorectal adenoma and 20 individuals submitted to autopsy who died of cardiovascular conditions unrelated to the large intestine. Colorectal carcinoma tissues will consist of samples of the lesion and of proximal adjacent mucous located 10cm from the lesion. Colorectal adenoma tissue will be obtained from the most representative area of the lesion while control tissues will be sourced from the individuals submitted to autopsy. Specimens will be mounted in TMA blocks prior to immunohistochemical study. The primary anti-bodies will be: APC, GSK-3, WNT-1, WNT-2, WNT-5, Axin, Ubiquitin, Beta-catenin, Frizzled 1 and Frizzled 5. Immunoreactivity will be analyzed using a validated semi-quantitative counting method. (AU)