FISH-RET

Message

Probes: RET (10q11.2)
Disease(s): Lung cancer, thyroid cancer

Test Code

LAB6025

CPT Codes
88377x1 manual or 88374x1 automated.

Preferred Specimen

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.

Instructions

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

Methodology
FISH

Report Available

4 days

Clinical Significance

RET gene rearrangements that result in growth-promoting chimeric or fusion proteins are found in 1-2% of adenocarcinoma-containing non-small cell lung cancer (NSCLC) and 20-40% of sporadic papillary thyroid carcinoma (PTC). In lung cancer, the most common rearrangement partner is KIF5B, followed by PTC1 and PTC3 rearrangements which are the most common in PTC. RET rearrangements in NSCLC are generally mutually exclusive of mutations in EGFR, KRAS, ALK, and ROS1. Patients tend to be younger (<60) and lack smoking history. Early clinical studies in NSCLC show response to multi-kinase inhibitors. By identifying PTC, RET rearrangements are one of several genetic markers useful for classifying indeterminate thyroid FNA cytology results. Sequence-variant mutations in the RET gene associated with MEN2 syndrome or sporadic medullary thyroid carcinoma (MTC) will not be detected by FISH; next-gen sequencing for the RET gene may be considered instead.

Performing Laboratory
Neogenomics Laboratories

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.