MGC4-2 with altered morphology and cytogenetics was more inductive than MGLN and MGRWV in chimeric prostate tumor growth in mice. A, chimeric C4-2-Luc tumors produced by coinjecting with MGC4-2 grew significantly faster than those from MGRWV, MGLN, or in the absence of MG cells (columns, mean of tumor volume of five independent measurements; bars, SE). C4-2-Luc alone failed to form tumors in mice (A). These data agree with serum PSA (B) and chimeric tumor epithelial cell-associated luciferase activity (C).