Expression of the nuclear oncogene p53 in colon tumours

Abstract

The nuclear tumour antigen p53 is expressed by a gene localized on the p-arm of human chromosome 17, a region frequently deleted in colon carcinomas. Using a monoclonal antibody to p53 antigen, immunohistochemical analysis of carcinomas and dysplastic tubular adenomas of the colon has been performed to study the relation between p53 expression and dysplasia or malignancy. With this methods p53 was detectable in 55 per cent of colon carcinomas (n = 29). In 8 per cent of adenomas (n = 74), focal nuclear p53 expression was found in dysplastic epithelial cells. In general, these p53-positive regions of the polyps were histologically indistinguishable from the neighbouring tubuli. Sometimes the p53-positive nuclei were found in a focus of more highly dysplastic epithelium. The results suggest that expression of the p53 gene may be part of the process of malignant transformation of dysplastic colon polyps.

The relationship of p53 immunostaining to survival in carcinoma of the lung

“…This percentage confirms our earlier study ) and compares favourably with the results from another smaller study on lung tumours (50% (Caamano et al, 1991)) and with work on breast (45.5%) (Cattoretti et al, 1988), colorectal (55%) (Van Den Berg et al, 1989) and (42%) (Scott et al, 1991) and ovarian cancer (50%) (Marks et al, 1991).…”

p53 expression in Reed-Sternberg cells of Hodgkin's disease

“…This would be akin to the hypothesis that p53 changes occur in malignant transformation from a dysplastic state (van den Berg et al, 1989;Pignatelli et al, 1992) or transformation from a low grade to high grade tumour (Sidransky et al, 1992).…”

Flow cytometric measurement of p53 protein expression and DNA content in paraffin‐embedded tissue from bronchial carcinomas

“…Originally thought to be an oncogene (24), it is now generally accepted that the wild-type p53 gene acts as a tumor suppressor gene (11,12). The p53 gene is located on chromosome 17p, a region that is often deleted in several types of human cancer, in particular colorectal carcinomas, but also in tumors of lung, brain, bladder, and breast (23,29,(31)(32)(33). Most tumors with allelic losses of chromosome 17p have missense mutations in the remaining p53 allele (29).…”

“…In addition, p53 can act as a nuclear oncogene by collaborating with Ha-ras in the transformation of rodent embryonic fibroblasts (8,24). Recent studies show that only the mutated p53 gene has this transforming capability (10,181. There have been few studies on the clinical relevance of p53 overexpression in human cancers (3,(5)(6)(7)19,26,27,30,32). In mammary carcinomas, p53 expression is associated with negative oestrogen-receptor status and high-grade malignancy (3).…”