• Test Code:
  • Department:
    Cancer FISH
  • Test Synonyms:
    RET kinase marker
  • CPT Code(s):

Gene fusions involving the RET tyrosine kinase are present in approximately 20-25% of papillary thyroid carcinomas. A number of partner genes have been identified (PTC1, PTC3, etc.). Treatment of advanced cases of RET-positive papillary thyroid carcinomas has proven successful with the inhibitors sunitinib and sorafenib.

Gene fusions involving the RET tyrosine kinase are also present in 1-2% of non-small cell lung carcinomas, primarily adenocarcinomas. Several partner genes (KIF5B, CCDC6) have been identified. The resulting activation of RET kinase activity appears to be a principal growth driver in these tumors.  Based on pre-clinical studies the KIF5B-RET fusion kinase is sensitive to sorafenib, vandetanib and sunitinib.  A break-apart FISH probe to the RET locus can be used to screen for these fusions by FISH.

Recommended Use:

The RET FISH test is recommended for screening NSCLC cases that are negative for an EGFR mutation and for an ALK fusion.  The test is also recommended for screening advanced cases of papillary thyroid carcinoma negative for BRAF mutation.


FISH is performed on sections of formalin-fixed, paraffin-embedded tumor tissue.   Slides are prepared per standard protocols and 100 interphase cells are scored.

Specimen Requirements:

Formalin-fixed paraffin-embedded tumor block or FFPE slides:  

  • If sending slides, please include H&E stained slide cut from same block
  • Preferred slice thickness is 4-5 microns on positively charged slides. 
  • Please submit 3-5 slides.  Store at room temperature.
  • Contact Client Services at (855) 535-1522 for shipping supplies and instructions.

Test Performed (Days):


Turn Around Time:

3-7 days

Shipment Sensitivity Requirements:

Ship via overnight express, using the FedEx priority overnight label provided.  Contact Client Services at (855) 535-1522 for shipping kits and instructions.


Additional Info: