This role has also been confirmed for other cancers including lung, thyroid, breast, and colorectal; (Zhu et al., 2011), In our study, concerning the lower level of Trx in patients with SCC and OLP in comparison to healthy individuals, another theory can be put forward for the role of Trx, as explained in the review study by Shabani et al., which mentioned a cancer preventive role for Trx. This evidence concerns the gene TXN and cancer.