title: Implications of MGMT methylation status in pituitary adenoma.
abstract: BACKGROUND
  Very little literature exists on frequency of MGMT methylation status in pituitary adenoma. We assessed the frequency of MGMT methylation and protein expression in pituitary adenoma and correlated with patients' age group and prognosis.
  
  
  METHODS
  Tumor tissues from 30 patients with pituitary adenoma were evaluated for MGMT promoter methylation status by methylation specific PCR method. All tumors were also immunostained with MIB-1, anti-p53 and anti-MGMT antibodies.
  
  
  RESULTS
  MGMT methylation status was noted in 40% of cases (7/20 non-functioning adenomas and 5/10 functioning adenomas). MGMT protein expression on IHC was noted in 72.2% of unmethylated tumors, while only 41.6% of methylated tumors demonstrated protein expression. The mean labeling index of MGMT protein was higher in unmethylated tumors as compared to the methylated group, though the difference was not statistically significant (18.6% vs 8.8%; p=0.131). Tumor regrowth occurred in four unmethylated tumors as compared to none in methylated group. Even though there was no correlation between patient age and MGMT methylation status (p=0.823), we noted that the frequency of methylation in middle age patients (between 30 and 59 yrs) was 64.7%, which was higher compared to other age groups.
  
  
  CONCLUSIONS
  This is the first study from India showing MGMT promoter methylation status with protein expression in pituitary adenoma. We noted that tumor regrowth was higher in unmethylated tumors.
authors.affiliation: Department of Neuropathology, National Institute of Mental Health and NeuroSciences, Bangalore, India.
authors.forename: Sneha
authors.initials: S
authors.lastname: Arya
authors.affiliation: Department of Neurosurgery, National Institute of Mental Health and NeuroSciences, Bangalore, India.
authors.forename: M A
authors.initials: MA
authors.lastname: Majaid
authors.affiliation: Department of Neuropathology, National Institute of Mental Health and NeuroSciences, Bangalore, India.
authors.forename: S D
authors.initials: SD
authors.lastname: Shwetha
authors.affiliation: Department of Neuropathology, National Institute of Mental Health and NeuroSciences, Bangalore, India.
authors.forename: K
authors.initials: K
authors.lastname: Sravani
authors.affiliation: Department of Neurosurgery, National Institute of Mental Health and NeuroSciences, Bangalore, India. Electronic address: arivazhagan.a@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Arivazhagan
authors.affiliation: Department of Neurosurgery, National Institute of Mental Health and NeuroSciences, Bangalore, India.
authors.forename: S
authors.initials: S
authors.lastname: Sampath
authors.affiliation: Department of Neuropathology, National Institute of Mental Health and NeuroSciences, Bangalore, India.
authors.forename: V
authors.initials: V
authors.lastname: Santosh
mesh_terms: D000236:Adenoma / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D000368:Aged; D019175:DNA Methylation / Q000235:genetics*; D015254:DNA Modification Methylases / Q000235:genetics*; D045643:DNA Repair Enzymes / Q000235:genetics*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007194:India; D008297:Male; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000235:genetics*; D011379:Prognosis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D025521:Tumor Suppressor Proteins / Q000235:genetics*; D055815:Young Adult
chemical_list: D025521:Tumor Suppressor Proteins; D015254:DNA Modification Methylases; C515491:MGMT protein, human; D045643:DNA Repair Enzymes
keywords: Adjuvant therapy; MGMT immunohistochemistry; MGMT methylation; Methylation specific PCR; Pituitary adenoma; Temozolomide