The RNA samples from HT-29 (ATCC) colon cancer cell line were reverse transcribed into cDNAs and categorized in 3 groups with different concentrations of 5-aza-deoxy-cytidine (5-Aza); in each group three replicative 150 mm cultures were treated with: 1) dimethyl sulfoxide (vehicle alone, 0 μM 5-Aza); 2) 5μM 5-Aza and 3) 10 μM 5-Aza; for five days We then used Affymetrix microarray platform to profile the gene expression of the 3 HT29 cell groups (3 replicates in each group) in order to search for differentially expressed genes Overall design: The transcriptional response of HT-29 (ATCC) colon cancer cell line under 3 concentrations of 5-aza-deoxy-cytidine was investigated based on their RNA expression profiles