Analysis of MGMT promoter methylation status on intraoperative fresh tissue section from frameless neuronavigation needle biopsy: a preliminary study of ten patients.
BACKGROUND
After a brain biopsy, the genetic analysis can fail because of insufficient material, extensive tumor necrosis, and formalin fixation under conditions that adversely affected the quality of the DNA or because the assay result was indeterminant. The freezing of fresh tumor tissue at surgery could greatly improve the success of DNA extraction and methyl guanine methyl transferase (MGMT) promoter methylation testing. The concentration of the DNA samples can also be improved from a withdrawal in an area with a high probability of neoplastic cells.


METHODS
The present study reports the results of ten frameless image-guided intracranial needle biopsies from April 2008 until February 2009, among a total of 28 frameless neuronavigation brain biopsy performed from May 2007 to February 2009. The protocol sampling provided withdrawal specimens correlated with neuroimaging characteristics of the lesions. The molecular determination of MGMT promoter was assessed with the nested methylation-specific polymerase chain reaction on fresh or cryopreserved needle bioptic tissue.


RESULTS
The genetic characterization was feasible in all the bioptic samples. The MGMT promoter was methylated in six patients, including a brain infection. The image-guided trajectory of the biopsy and the intraoperative frozen section increased the diagnostic yield.


CONCLUSIONS
To the best of the authors' knowledge, this is the first report with the MGMT promoter status analysis on needle bioptic fresh tissue. In the future, the availability of the molecular genetic characterization of a brain tumor before open surgery will provide important information for the optimal treatment.
Iaccarino
Corrado
C
Hub & Spoke Neurosurgery Unit-Emergency Department, University Hospital of Parma, Viale Gramsci, 14, 43100, Parma, Italy. iaccarin@tiscali.it
Nicoli
Davide
D
Gallo
Carmine
C
Nasi
Davide
D
Pisanello
Anna
A
De Berti
Gianni
G
Ghadirpour
Reza
R
Marcello
Norina
N
Servadei
Franco
F
D000328:Adult; D000368:Aged; D001707:Biopsy, Needle / Q000379:methods; D001921:Brain / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D001932:Brain Neoplasms / Q000737:chemistry / Q000235:genetics / Q000601:surgery; D015331:Cohort Studies; D019175:DNA Methylation / Q000235:genetics; D015254:DNA Modification Methylases / Q000235:genetics*; D045643:DNA Repair Enzymes / Q000235:genetics*; D005260:Female; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D038361:Neuronavigation / Q000379:methods*; D010865:Pilot Projects; D011401:Promoter Regions, Genetic / Q000235:genetics*; D025521:Tumor Suppressor Proteins / Q000235:genetics*
D005819:Genetic Markers; D025521:Tumor Suppressor Proteins; D015254:DNA Modification Methylases; C515491:MGMT protein, human; D045643:DNA Repair Enzymes