STAT1 and neoplasm: To verify the observed effects of STAT1 silencing in vivo, we compared the growth of tumors formed by HeLA/vector, HeLa/Fra-1, and HeLa/Fra-1/siSTAT1 cells in BALB/c-nu mice Tumor formation was significantly diminished in the HeLa/Fra-1 group compared with that in the HeLa/vector control group.