A Commonly Deleted Gene in Multiple Cancers
What is MTAP?
MTAP is important for the function of PRMT5, itself a critical regulator of an abundance of proteins in human cells. MTAP is deleted in cancers as a “passenger deletion” along with the tumor suppressor gene CDKN2A — a common cancer-promoting genetic event.
The MTAP gene is deleted in 10-15% of all human cancers
There are currently no FDA-approved treatments specifically for patients with MTAP-deleted cancers. Several clinical trials are evaluating investigational treatments targeting MTAP-deleted cancers, including two phase 1/2 clinical trials sponsored by Tango Therapeutics.
Detecting MTAP Deletion
At the time of diagnosis, it is useful to test the tumor tissue obtained by biopsy for cancer-related genetic alterations to help determine the best treatment plan for the patient. This type of testing is typically done with next-generation sequencing (NGS) that can directly identify almost all known genetic alterations associated with cancer, or immunohistochemistry (IHC) which identifies specific changes in the amount of protein caused by those alterations. MTAP deletions can be detected by either method and used to determine eligibility for clinical trials, including the phase 1/2 trials for TNG908 and TNG462.
If testing was not done at diagnosis, it can still be done years later on tissue samples stored by the hospital where the biopsy was performed.
Using Prior Test Results
If a patient’s tumor has been tested previously by NGS (or IHC), review the results for any of the following:
Present by NGS or negative by IHC
Present by NGS
Negative by IHC
- Malignant Peripheral Nerve Sheath Tumor (MPNST)
- Non-small cell lung cancer (NSCLC)
- Pancreatic Cancer