In the present study effects of TCE on the cell cycle regulating genes in TCE-exposed workers were investigated. None of the previous studies reported the possible role of miRNA let-7c in regulation of PPARA gene expression in lymphocytes of people occupationally exposed to TCE. In this study we observed the effect of TCE exposure on cell cycle regulating genes along with a possible mechanism of action and regulation of TCE metabolites in 49 TCE-exposed workers. We examined exposure -related differences in mRNA levels of p53, p21, bax, bcl2, p16 andc-myc among individuals occupationally exposed to TCE and controls.