Figure 3. Experimental verification of key genes in ESCC. (A) qRT-PCR analysis of key genes in tumor (T) and normal (N) tissues of twenty paired ESCC samples. (B) Scatter plot of qRT-PCR analyses for key genes in seven ESCC cell lines. Blue spots represent cells treated with DMSO, whereas the orange spots represent cells treated with 5-aza-dC. (C) Colony formation assays of ESCC cells after 5-aza-dC treatment. ESCC cells were plated in 6-well plates. After 24 h, the cells were treated with 5-aza-dC. Cultures were maintained for six days, and cells were then stained and photographed. DMSO was used as the control. Colony formation assays illustrate that hypermethylation of key genes plays an important role in cell growth.