ORTHOTOPIC IMPLANTATION OF HUMAN COLON-CA NCER INTO NUDE-MICE - METHODOLOGY AND PATHOPHYSIOLOGICAL INTEREST

Objectives. - The xenograft of human cancers into athymic nude mice ma kes it possible to obtain abundant tumour material and deepen biologic al characterization. Usually, the tumours are grafted into the subcuta neous tissue whose environment is indeed different from that of origin al colon cancer. Methods. - In older to transplant tumours into an ort hotopic environment, intra-caecal implantation of colon cancers was pe rformed. A tumour fragment (30 mm(3)) was deposited at the surface of serous membrane of the caecum, previously scrapped, fixed with a threa d and recovered with biologic glue. Six different types of colon tumou r, previously adapted to transplantation in nude mice, were similarly grafted. Results. - Twenty to forty days after transplantation, tumour takes were observed with a similar rate by the subcutaneous or intra- caecal graft (93 % of 115 and 96.8 % of 154 transplantations, respecti vely). Tumour growth varied between the tumours implanted into the two sites. Moreover, only the tumours intracaecally transplanted develope d nodal and liver metastases. Histological examination revealed the in vasion of the muscle layer, submucosal tissue and mucosal membrane by tumour cells and the mixture of normal glands and neoplastic glands. C onclusions. - This technique of orthotopic implantation of colon cance r samples will contribute to obtain an experimental model for colon ca ncer research.