EXPRESSION OF MUTANT P53 PROTEIN AND CD44 VARIANT PROTEINS IN COLORECTAL TUMORIGENESIS

Colorectal tumorigenesis evolves through a series of molecular genetic changes, providing putative markers for tumour progression. This stud y investigated the relation between expression of the tumour suppresso r gene p53 and splice variants v5 and v6 of the cell adhesion molecule CD44 by immunohistochemistry on tissue samples of early adenomas (n=1 2), late adenomas (n=12), Dukes's A and B carcinomas (n=21), and Dukes 's C and D carcinomas (n=22) and compared these results with expressio n of these proteins in normal colonic mucosa (n=17). A statistically s ignificant trend of increasing expression was seen for both p53 (p<0.0 05) and CD44 variant exon v6 (p<0.0005) in subsequent stages of this t umour progression model. High expression of CD44 v5 was seen in most c olorectal neoplasms (83%-96%), independent of stage. A statistically s ignificant correlation was present between p53 expression and expressi on of variant v6 of CD44 (p<0.01). Both p53 expression and CD44 v6 exp ression in adenomas increased with the degree of dysplasia (p<0.05). T he results of this study show that mutant p53 protein and variant v6 o f the CD44 glycoprotein are markers of tumour progression in colorecta l cancer.