GENETIC ANOMALIES AND COLORECTAL-CANCER

The prognosis of colorectal cancer has been based essentially on patho logical data for many years. The analysis of genetic anomalies has led to fundamental progress and clinical advances. Genetic anomalies are routinely studied. 1 - Flowcytometry evaluates the quantity of DNA in the nucleus during the cell cycle. 2 - Cytogenetics is the study of ca ryotype anomalies by loss or gain of chromosome material and structura l changes. 3 - Molecular biology gives a means of recognizing chromoso me losses and especially to study oncogenic or antioncogenic mutations . These analyses allow: 1 - an evaluation of their value as a prognosi s factor and thus their use for indicating adjuvant medical and/or sur gical treatments. 2 - an understanding of cancerogenic processes. 3 - the development of future therapeutic techniques based on a better und erstanding of the mechanisms involved. 4 - familial concelling in high risk families and an examination of responsible or favouring genes in certain familial cancers. Research into familial forms has recently l ed to the demonstration of genetic alterations located on chromosomes 1 and 2. These anomalies called RER correspond to alterations found on tumors. Studying these alterations will allow better prediction of hi gh risk subjects in cancer families without polyposis.