Colorectal cancer is the second leading cause of cancer-related death in the Western industrialized world. Many epidemiological studies have shown a negative association between colorectal cancer incidence and vitamin D levels. It has been suggested that the antitumoral action of 1,25(OH)2D3 in colorectal cancer relies on several mechanisms at the cellular level. This prompted us to evaluate expression of certain immunohistochemical markers during tumor progression in colorectal human tissue and to study for the first time the relationship between histological type and grade of colorectal tumors with the expression of these markers. The investigated markers were the ones responsible for apoptosis (PAK1 and p53), cell adhesion (beta-catenin), differentiation (p53), and proliferation (Ki67). We also analyzed the correlation of their expression with vitamin D blood levels in these patients. Our results showed that the expression of these biomarkers increased with progression from colorectal adenomas to carcinomas. Expression of PAK1, beta-catenin, and p53 in the nucleus correlated with advanced stages of carcinoma. Low vitamin D blood levels correlated with nuclear accumulation of p53, nuclear beta-catenin expression, and expression of Ki67.
Part of the book: A Critical Evaluation of Vitamin D