Genes deregulated by (S)-NNN in esophageal and oral mucosa of rats are differentially expressed in oral and head neck cells at different stages of transformation. (A) Selected genes from those deregulated by (S)-NNN in esophageal and oral mucosa of rats were analyzed in RNA samples from NHOK, OKF6, Msk-Leuk1, TR146, SCC17B and SCC58 cells by qRT-PCR as described in the Materials and Methods section. Expression levels are shown in arbitrary units on the Y axis, whereas the different cell lines are shown on the X axis. (B) Validation of EPHX2 alteration in the different cell lines by Western immunoblot analysis. The assays were performed three times as described in Materials and Methods and the results are presented as mean ± SD. Equal loading of protein was confirmed by stripping the immunoblot and reprobing it for β-actin. Statistical significance was assessed relative to level of the protein in OKF6 cells using one–way ANOVA and a post Tukey’s test; *p < 0.05