Zeta MGMT Antibody. Zeta’s recombinant mouse antibody recognizes MGMT, a DNA repair protein that reverses DNA damage induced by alkylating agents and acts as a suppressor of mutation and carcinogenesis. Methylation of of the promoter sequence of the MGMT gene silences the MGMT, making tumor cells more sensitive to treatment with cancer chemotherapeutic alkylating agents, which act by inducing the formation of lethal cross‐links at the O6‐ alkylguanine position in DNA. MGMT transfers alkyl adducts from the O6‐position of guanine in DNA (prior to cross‐link formation) to a cysteine residue in its own sequence, thereby restoring DNA to its intact state. This transfer inactivates the MGMT enzyme and is irreversible; hence the level of MGMT in a cell is directly proportional to the level of DNA‐damage toleration. Tumors with high levels of MGMT are likely to be drug resistant.
MGMT immunohistochemistry (IHC) is being evaluated in many studies as a biomarker for chemotherapy treatments, and for example, may have validitity as a biomarker for response to combination therapy with capecitabine and temozolomide in patients with advanced neuroendocrine carcinomas.