Prognostic significance of different biomarkers (DNA content, PCNA, karyotype) in colorectal adenomas.

Immunohistochemical detection of proliferating cell nuclear antigen (PCNA), densitometric analysis of nuclear DNA content and fluorescence in situ hybridization with centromere-specific DNA probes to chromosomes 11 and 17 were carried out on histological sections from 55 colorectal adenomas, in order to identify those adenomas that are more likely to progress to cancer. A considerable variability of PCNA positivity (range: 23-28.2%; mean value: 12.8%), a DNA indexfrom 1 to 2.3 and numerical alterations of chromosome 11 were observed. In particular, 14 out of 55 adenomas (25%), independent of histological type, degree of dysplasia, location and size, showed a DNA-aneuploid content, trisomies and tetrasomies of chromosome 11 and high PCNA index. It was concluded that the combination of some biomarkers (additional chromosomes 11, high PCNA and DNA indices) may allow identification of more aggressive colorectal adenomas with increased ability to undergo malignant transformation.