Methodology
FISH
Test Description

Probes: CDKN2A (p16) (9p21) | Centromere 9
Disease(s):  Mesothelioma

Clinical Significance

Detection of homozygous deletions of CDKN2A (also called p16) by FISH is useful to distinguish malignant pleural mesothelioma (MPM) and diffuse malignant peritoneal mesothelioma (DMPM) from reactive mesothelial hyperplasia (RMH) and epithelial ovarian cancer (EOC). While morphologic, immunocytochemical, and immunohistochemical analyses determine the mesothelial origin of such neoplasms, CDKN2A FISH enables differentiation of benign from malignant proliferations with high specificity and positive predictive value, particularly when combined with BAP-1 IHC. Homozygous deletions have been reported in 70-80% of MPM cases and are associated with shorter survival in these patients.

Specimen Requirements
  • Bone marrow aspirate: N/A
  • Peripheral blood: N/A
  • Fresh, unfixed tissue: N/A
  • Fluids: N/A
  • Paraffin block: Send paraffin block. Also send circled H&E slide for tech-only (required).
  • Cut slides: H&E slide (required) plus 4 unstained slides cut at 4-5 microns. Circle H&E slide for tech-only.
Storage and Transportation

Use cold pack for transport, making sure cold pack is not in direct contact with specimen.

CPT Code(s)*
88377(x1) Manual or 88374(x1) Automated
Turnaround Time

4 days

Level of Service
Global
Technical

*The CPT codes provided with our test descriptions are based on AMA guidelines and are for informational purposes only. Correct CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed.