MUC5AC and neoplasm: On the other hand, gene expression levels (2^-ddct) of tumor suppression genes in CaCO2 cells; p53, Rb, APC, and PTEN showed increased expression in cells treated with the mucin extract by (31.5, 26.2, 34.8 and 31.0), respectively when compared to the cells treated with lead nitrate (10.7, 6.5, 9.6 and 6.0).