Immunohistochemical expression of MGMT in gliomas and its role in ascertaining patient survival
Introduction. MGMT (O-6-methylguanine-DNA methyl transferase) is a DNA repair enzyme with implications on chemoresistance and subsequent patient prognosis. This study investigated the association of MGMT with the various grades and subtypes of gliomas and evaluated the associated clinical outcome of these patients.
Methods. This observational longitudinal follow up study spun over a period of 36 months and included 33 patients with primary glioma who underwent surgical interventions and chemoradiotherapy at a tertiary care center in Kolkata. The surgical samples were processed and histopathologically typed. Immunohistochemical analysis was done using anti- MGMT antibody and MGMT status was determined. Patients were followed up for 3 years.
Results. Males were 1.3 times more commonly affected by gliomas. Mean age was 42.9 years for females and 47.2 years for males. Frontal lobe was the most commonly involved site whereas focal neurological deficit was the most common symptom. Karnofsky performance score was higher for low grade gliomas and lower for high grade gliomas (p=0.04). Significant association was found between histopathological grade and MGMT immunoexpression (p=0.0001) as well as histopathological subtype and MGMT status (p=0.0036). On follow up, mean survival of the patients was 25.4 months. Significant association was found between MGMT status and survival of the patients (p=0.0437).
Conclusion. MGMT immunoexpression is significantly associated with different grades and subtypes of gliomas. In addition, MGMT has significant implications on chemoresistance and patient survival. Hence, MGMT expression should be mandatorily checked before starting the chemotherapy.