GROWTH-FACTOR REQUIREMENT, ONCOGENE EXPRESSION AND TP53 MUTATIONS OF A TUMORIGENIC AND A NONTUMORIGENIC SUBLINE OF THE HUMAN BREAST-CARCINOMA CELL-LINE, HMT-3909

From a human breast carcinoma cell line, HMT-3909, a tumorigenic and a non-tumorigenic subline have previously been described. Cells of both sublines have been characterised as carcinoma cells. In the present w ork we examined whether differences in growth factor requirements or o ncogene expression may explain the difference in tumorigenicity. We fo und that exogenous growth factor dependence discriminated between the two sublines. No alterations in oncogenes or tumour suppressor genes w ere demonstrated that could explain the differences in tumorigenicity. The lower growth factor requirement and the higher growth rate of the tumorigenic subline indicates that, in these cells, growth potential may determine the outcome of the tumorigenicity assay.