Potentiation of Metastatic Capacity by Transforming Growth Factor‐β1 Gene Transfection

This study was designed to assess whether the excessive secretion of transforming growth factor‐β1 (TGF‐β1) by Chinese hamster ovary (CHO) cells transfected with TGF‐β1 gene may be linked to the development of a metastatic phenotype. We observed large numbers of metastatic colonies in the lungs of nude mice inoculated with the transfected CHO cells. The tumors derived from these transfected cells demonstrated marked angiogenesis. We postulate that the overproduction of TGF‐β1 by these tumors may participate in the metastatic progression following establishment of angiogenesis at the primary tumor site.