Transformation of cultured human embryonic fibroblasts by oncornavirus like particles released from a human carcinoma cell line

A fibroblast like cell culture was established from a stomach biopsy of a patient with metastatic adenocarcinoma. One of the cultures, at the 6th passage level, left unattended for a month at 37°, produced numerous foci of epithelial cells. Upon subculturing, an epithelial cell line, designated HCCL (human carcinoma cell line), was established. The HCCL cells released particles possessing the characteristics of oncornaviruses: density 1.175 g/ml, cores with a density of 1.22-1.26 g/ml, high molecular weight RNA (60-70S) and RNA instructed DNA polymerase activity (deoxynucleosidetriphosphate:DNA deoxynucleotidyltransferase, EC 2.7.7.7). Inoculation of particles released from HCCL cells into cultures of human embryo muscle fibroblasts resulted in the appearance of foci of transformed cells.