Methodology: FISH

Clinical Significance:
Deletion involving the cyclin-dependent kinase inhibitor 2A/p16 gene at the 9p21 locus on chromosome 9 is frequently observed in mesothelioma. Homozygous deletion of this gene has been reported in 22-74% of mesotheliomas. This characteristic of mesotheliomas can be employed in the often-difficult differential diagnoses of spindle cell mesothelial proliferations where immunohistochemical markers cannot distinguish between benign and malignant mesothelial proliferations. While a negative result for homozygous p16 deletion cannot rule out the possibility of a mesothelioma, a positive result is highly specific for mesothelioma in the appropriate clinical setting.

Organ: Lung

Disease State: Mesothelioma vs. Adenocarcinoma

CPT Code(s): 88374 (reference only; CPTs may vary)

Turnaround Time: Within 4-6 business days of receipt

Schedule: Monday - Friday

Specimen Requirements:
• Formalin-fixed, paraffin-embedded tissue block or cell block - OR - • Minimum of 5 unstained slide cut at 4µm for each test requested