Heterogeneity in proliferation markers in colorectal cancer.

BACKGROUND

The intratumoral heterogeneity in different markers of proliferation, and the immunohistochemical overexpression of the p53 protein-a possible regulator of proliferation-have been investigated to only a minor extent in colorectal cancer. The evaluation of tumour biopsy samples, especially preoperatively, when multiple sampling is not always feasible, must be based upon markers being more or less homogeneously expressed.

MATERIALS AND METHODS

Three different DNA-labelling techniques were investigated in multiple biopsy samples (2-10, median 4) from 19 tumours obtained from 18 patients. Anti-bromodeoxyuridine and Ki-67 monoclonal antibodies were used to detect nuclei of proliferating cells in adjacent tumour sections. Adjacent tumour material was analysed by flow cytometry of propidium iodide labelled nuclei. In addition, overexpression of the p53 protein was detected using the monoclonal anti-p53 antibody DO-7

RESULTS

There was considerable intratumoral heterogeneity in the labelling indices. No correlation was found between overexpression of the p53 protein and markers for proliferation, as indicated by observations made using three different methods. In contrast, the staining for p53 protein was either homogeneously positive or negative.

CONCLUSIONS

The results indicate that analyses of proliferation in preoperatively obtained tumour biopsies are of limited value for prognostic prediction, or other purposes, in view of the extensive intratumoral heterogeneity shown with three different markers.