Relation of in vitro properties to tumorigenicity for a series of sublines of the human breast cancer cell line MCF-7.

The relation of in vitro properties to tumorigenicity was studied using eight sublines of the human breast cancer cell line MCF-7. Four of the eight were tumorigenic in estrogen-treated nude mice. The sublines differed for each of the in vitro properties measured, and no property correlated perfectly with tumorigenicity. Cytochalasin B-induced multinucleation was a property of all four tumorigenic sublines but of only one of the four nontumorigenic ones. Anchorage-independent growth and concanavalin A-mediated hemadsorption levels were higher in all sublines than reported levels for nontransformed fibroblasts and normal human or mouse mammary epithelial cells. The production of both plasminogen activator and a plasminogen-independent fibrinolytic activity showed no relationship to tumorigenicity but was higher in those sublines producing more invasive tumors. It appears that no one of these in vitro properties is sufficient to make a subline tumorigenic. Rather, the first three properties studied here and, perhaps, also production of plasminogen activator may each be necessary, but not sufficient, to make a subline tumorigenic. In addition, properties such as production of plasminogen activator and other proteases, while perhaps not essential to tumorigenicity, may confer characteristics, such as invasiveness, on the tumors produced by a given subline.