Human chromosome analysis in 24 cases of primary carcinoma of the large intestine: contribution of the G-banding technique.

As in the haemopathies, the application of cytogenetics to epithelial cancers could aid in the study of their pathogenesis evaluation. In this context we performed chromosome analyses on a series of human colo-rectal cancers. The technique was consistently reliable since the modal number of chromosomes could be determined in all 24 cases. In 22, karyotypes could also be established. Each tumour was characterized by a single cell clone in 21 cases and by a mosaic of 2 populations in 3 cases. Numerical anomalies were not due to chance: they enabled near-diploid (11 cases), near-triploid (9 cases), mosaic (3 cases) and highly polyploid (1 case) cancers to be distinguished. Supernumerary chromosomes were primarily in groups C and F. The most frequent markers before denaturation techniques were No 2q +, No F and minutes. Each time double-minutes were observed (5 cases), they were in invasive cancers (B and C Dukes classification). Cells were generally diploid in non-invasive cancers with fewer quantitative and structural anomalies. Tumour cytogenetics were related to the histological type and localization in the colon, as well as to the local and metastatic spread.