Being able to detect and monitor brain tumor has been one
the biggest challenges till date for neurologists. Diagnosing a brain tumor
often involves a series of invasive neurosurgeries. It would be a boon for
clinicians if they manage to catch and treat malignant neoplasms without a
biopsy.
Well, the problem seemed to last forever unless researchers
at Massachusetts General Hospital (MGH) presented a digital PCR-based approach
for the detection of IDH1 mutation in cerebrospinal fluid (CSF) samples of
patients. Digital PCR, at its core, is simply a
single molecule counting method that quantitatively measures absolute DNA and
eliminates the need for standard curves.
The digital PCR-based approach of Drs.Breakfield
and Hochberg accurately detected the presence and abundance of tumor-associated
IDH1 mutation in the CSF of five of the eight patients, who were known to have
IDH1 mutant tumors. The remaining three who showed false-negative results
actually had low-grade tumors.
The current approach for patients who may have a brain tumor
is a cumbersome process. Firstly, they have to undergo a brain scan followed by
a biopsy to determine whether the growth is malignant. A second operation is
also required sometimes to remove the tumor prior to beginning radiation
therapy and chemotherapy. But still none of these treatments target to the
specific molecular nature of the tumor.
According to Dr. Hoschberg, a molecular diagnostic assay like
The PCR-based test he and his team presented would allow the physicians to
immediately initiate the optimum treatment of the patient without the need for
surgical biopsy. In a statement, he added” For some patients, the treatment could shrink a tumor before
surgical removal, for others it may control tumor growth to the point that
surgery is not necessary, which in addition to keeping patients from undergoing
an unnecessary procedure, could save costs.”
Since a number
of pharmaceutical companies are developing drugs that specifically target the
tumor-associated IDH1 mutant enzyme, the knowledge of the IDH1 mutation of the
tumors could help guide treatment decisions.
However, the
effect of tumor grade and size on the ability of this PCR-based approach is
still a thing to look for. Still, the researchers are hopeful to translate
their findings into meaningful results in the clinic. They feel that reliable
detection of tumor-associated mutations in CSF samples with digital PCR would
provide a biomarker for monitoring and tracking tumors without invasive
neurosurgeries.
