Monday, February 4, 2008

MGMT and MGMT promoter hypermethylation testing not ready for prime time

A few months ago, an oncologist at my institution asked for an MGMT promoter hypermethylation assay on a high grade glioma. I looked into the issue, and discovered that testing is not standardized yet and really not ready for clinical use. In a review article on molecular testing of gliomas in the January '08 issue of Journal of Neuropathology and Experimental Neurology, the authors concur with this position. That being said, if anyone does want to do immunohistochemistry (IHC) for MGMT, Dr. Roger McLendon at Duke performs this test. Some would argue that PCR is better than IHC, but the good Dr. McLendon counters that immunohistochemistry is more reliable as it correlates with enzyme activity while the PCR promoter methylation assay does not. In any case, I got the oncologist to cancel her request for MGMT promoter methylation studies.

7 comments:

JD said...

RedPath in Pittsburgh stopped doing their assay. Unfortunately, the oncologists here are addicted to it. We found a researcher who's willing to do it completely off the medical record because of potential legal liability. What was great about RedPath was their willingness to charge the patient's insurance for the test. If Dr. McLendon is willing to do the same, I'd consider sending him my specimens. However, if he would charge the hospital, then that would be out of the question.

Hopefully, you'll also post the cover of the April issue of JNEN!!!

Brian E. Moore, MD said...

Do you know what the status is with regard to coverage of the MGMT test by insurance? Thanks,
BEM

JD said...

When RedPath did the test, they billed the patient's insurance. Private hospitals that do the test probably wouldn't do that--they would bill the department, which is unacceptable.

Brian E. Moore, MD said...

So, why did RedPath stop doing their assay?

JD said...

I don't know if it's a patent infringement issue or a problem with the assay itself. I hope they're able to get up and running again soon.

In the meantime, I still send them all my specimens for genetic testing (e.g. 1p/19q and EGFR). They do a great job.

JD said...

I'm getting block requests all the time from the Harvard hospitals looking to do EGFR and MGMT testing. Just got another one.

CColl said...

I have a glio patient who scored 93%, tolerated TMZ very well and is now in his 16th month of survival. A study I read, Journal of Cancer Science and Therapy, 6:136-141 (2014) suggests that a bias exists in the studies on MGMT and prognosis due to the lack of short term survivors. They further suggest that studies should be performed on those patients 6 months or more out only. Before that time the predictive quality is too low. Why not perform the test consistently on these patients?