Investigation of the Effect of Zebularine in Comparison to and in Combination with Trichostatin A on p21Cip1/Waf1/Sdi1, p27Kip1, p57Kip2, DNA Methyltransferases and Histone Deacetylases in Colon Cancer LS 180 Cell Line. The gene discussed is CDKN1A; the disease is colonic neoplasm.