MUC4 and neoplasm: The tumor volume from MUC4 knockdown cells was significantly smaller (p = 0.0001) and the tumors excised at 8 weeks had markedly reduced weight, compared with tumors obtained from control cells (mean 0.171±0.05 g in MUC4 knockdown vs. 0.653±0.07 g in control cells) (Figure 5B).