Angiogenesis and neoplastic progression in vitro.

In vivo cell populations at high risk of neoplastic transformation have been shown to acquire the ability to induce new formation of vessels. The present experiments tested whether the same change occurred during neoplastic transformation in vitro. In four cell populations (human HBL 100 mammary epithelium, BALB/c fibroblasts, C57BL-MG epithelium, and Syrian golden hamster embryo cells), angiogenic capacity appeared during their cultivation in vitro and was evident long before a neoplastic transformation could be recognized. The data were interpreted to support the hypothesis that acquisition of angiogenic capacity by a cell population normally devoid of this capacity indicates an increased risk of neoplastic transformation.