EGFR particularly stimulates downstream targets of the pro-oncoproteins family such as RAS-RAF-MEK-ERK and AKT-PI3K-mTOR signaling pathways (ZHANG and LIU, 2002). In cancer cells, the overexpression of EGFR, and the mutant downstream effectors such as KRAS, BRAF, PIK3CA, P53 and PTEN have been linked to a dynamic change that occurs in cancer cells leading to drug resistance, distinct oncogenicity alteration,

Aim: To investigate potential DNA methylation in methylcytosine dioxygenases and correlation of TET genes with vitamin B12/ferritin levels in cancer patients. Materials & methods: 200 blood samples were obtained from both cancer patients and healthy individuals. Results: The expression of DNMT1, DNMT3a and DNMT3b was increased in patients with low vitamin B12 and ferritin levels, while the expression of MTR, TET1 and TET3 significantly decreased. DNA methylation analysis in patients with deficient vitamin B12/ferritin levels showed methylomic changes within the location 318/CG and 385/CG in the promoter region of TET1 and TET3, respectively. Conclusion: Vitamin B12/ferritin deficiency contributes to DNA methylation progress in cancer patients.