Multiplex allele-specific PCR with capillary electrophoresis detection.
TERT (telomerase reverse transcriptase) is involved in maintaining the length of chromosome telomeres. The TERT gene is normally expressed in germ cells and stem cells but is repressed in postnatal somatic cells. Because chromosomes are shortened with each round of DNA replication, cells without telomerase activity have a limited number of divisions before apoptosis occurs. Telomerase activity, therefore, plays an important role in immortalizing the cells of many types of cancer. A common mechanism of increased telomerase activity in cancer is mutation of the TERT promoter. These mutations create a consensus binding site for ETS transcription factors leading to increased TERT expression. The detection of TERT promoter mutations can be useful in assessing the malignant potential of some lesions such as melanocytic lesions or in distinguishing certain types of cancer from benign histologic mimics. In addition, for some cancer types, such as papillary thyroid carcinoma, melanoma and glioma, TERT promoter mutations are associated with an inferior prognosis. This test uses allele-specific PCR to detect TERT promoter mutations including c.-146C>T (C250T; Chr.5:1295250C>T), c.-124C>T (C228T; Chr.5:1295228C>T), c.-138_139CC>TT (Chr.5:1295242_1295243CC>TT) and c.-124_125CC>TT (Chr.5:1295228_1295229CC>TT). Genomic positions are based on hg19 assembly NC_000005.9.
Interpretive report provided.
A negative result does not rule out the presence of a rare mutation or a mutation below the limit of detection (5% mutant allele). In addition, the absence of a TERT promoter mutation does not exclude malignancy or malignant potential.
3 – 10 days
For formalin-fixed, paraffin-embedded tissue, a block containing an area with a high percentage of neoplastic cells (for micro-/macro-dissection) is preferred. Unstained, UNBAKED slides (5-8, 10-micron slides; 10-15 if few neoplastic cells are present) with associated H&E stained slide are also acceptable. Decalcified tissue or other fixatives will be accepted and the assay attempted, however these may result in failed testing due to degraded nucleic acid. Both blocks and slides should be stored at room temperature. A Diff-Quik stained aspirate smear (preferably containing a high percentage and overall amount of neoplastic cells) is also acceptable. Store at room temperature.
By ordering this test the clinician acknowledges that informed consent has been obtained from the patient as required by applicable state or federal laws and the ordering clinician has authorization from the patient permitting MLabs to report the test results to the ordering clinician. Test includes microdissection billed as a separate additional charge. Test includes pathologist interpretation of results billed as a separate additional charge. This test is not available without interpretation.