RB1 and neoplasm: Gene expression levels (2^-ddct) of tumor suppression genes in HepG-2 cells; p53, Rb, APC, and PTEN showed increased expression in cells treated with the mucin extract by (43.2, 43.6, 45.4 and 39.6), respectively when compared to the cells treated with lead nitrate (24.2, 17.9, 12.8 and 13.9).