PTEN (10q23.32) and TMPRss2-ERG (21q22.2) loci are assessed by fluorescent in situ hybridization (FISH) using three-color MetaSystems XCyting locus-specific probes. Aberrations of ERG (deletion, copy number increase, and rearrangement) have been reported in prostate cancer. Deletions of PTEN have been reported in prostate cancer.
disease state indication(s)
The Phosphatase and Tensin Homolog (PTEN) is a tumor suppressor gene located on cytoband 10q23.3, and has been found to be deleted in up to 50% of prostate cancer cases. The normal activity of PTEN is thought to be control of cell growth and proliferation through the AKT signaling pathway. Loss of the gene (and therefore, presumably, full protein function) has been shown to result in dysregulation of this pathway, thus allowing for increased growth and proliferation of tumor cells. PTEN deletions have been commonly identified in numerous solid tumors, including prostate and endometrial cancers. Evaluating for PTEN using FISH technology allows for determination of whether there is loss of the PTEN gene, and if the deletion is hemizygous (one allele) or homozygous (both alleles). Recent studies have demonstrated that both hemizygous and homozygous PTEN deletions in prostate cancer appear to be correlated with tumor progression and more aggressive disease. Furthermore, homozygous deletion seems to be associated with a higher likelihood of biochemical recurrence and decreased overall survival.
The Erythroblast transformation specific Related Gene (ERG) is located on chromosome 21. Initial studies of the involvement of the ERG gene in prostate cancer identified a fusion with the TMPRSS2 gene. More recent studies have discovered that there are multiple genomic alterations (deletion, copy number increase, rearrangement, etc.) of the ERG gene that correlate with prostate cancer-specific survival and biochemical recurrence.
Fluorescence in situ hybridization (FISH)
specimen type and requirements
BxChip and/or formalin fixed paraffin embedded (FFPE) sections - two (2) unstained slides and one (1) H&E slide 4-5 micron thick.
Tech-only (TC): 3 days
Global (TC & PC): 5 days
medicare moldx cpt code
Laboratory developed test (LDT)
Global (TC & PC) or Tech-only (TC)