CA12 and neoplasm: Irradiation of ca12-silenced tumors (LS-shca9/ca12- -DOX +IR) reduced the growth rate compared to non-irradiated tumors (LS-shca9/ca12- -DOX) to the same extent observed for irradiation of control tumors suggesting that ca12 alone is not able to confer tumor radioresistance (Figure 4B).