CYTOGENETIC COMPARISONS OF SYNCHRONOUS CARCINOMAS AND POLYPS IN PATIENTS WITH COLORECTAL-CANCER

Thirty tumorous lesions from seven patients with colorectal cancer wer e short-term cultured and cytogenetically analysed: 16 non-adenomatous polyps, six adenomas, seven carcinomas, including one in polyp, and o ne lymph node metastasis. Clonal chromosome aberrations were found in 20 samples in 100% of the carcinomas, in 100% of the adenomas and in 3 7.5% of the non-adenomatous polyps, i.e. all ten lesions with a normal karyotype were histologically diagnosed as hyperplastic polyps. Altho ugh adenomas and carcinomas shared several karyotypic features, two ch romosome aberrations, der(8;17)(q10;q10) and -14, were found in carcin omas but not in adenomas, indicating that they might be specifically a ssociated with carcinoma development in the large bowel mucosa. The ka ryotypic similarity seen between the malignant and benign tumours in t he same patient, and also sometimes among non-malignant polyps in the same case, indicates that these microscopically distinct lesions may b e part of a single neoplastic clonal expansion.