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Immunohistochemistry (IHC)
Test Description
p27 (KIP1) belongs to the family of cell cycle regulators that cause cell cycle arrest in G1 phase. p27 promotes apoptosis, plays a role in terminal differentiation of some tissues and mediates chemosensitivity in solid tumors. Decreased p27 KIP1 expression in tumors is associated with a more aggressive tumor phenotype such as poor histologic grade, presence of lymphovascular invasion and higher growth fraction. These findings have been validated on various cancers such as breast, colon, esophagus, stomach, lung and prostate.
Specimen Requirements
  • A formalin-fixed, paraffin-embedded (FFPE) tissue block is preferred specimen type


  • One (1) unbaked, unstained slide for H&E staining (required) and two to three (2-3) positively charged unstained slides (all cut at 4-5 microns) for each test/antibody ordered

  • Block and slide identifiers should be clearly written and match exactly with the specimen ID and specimen labeling as noted on the requisition.

Storage and Transportation
Use cold pack for transport. Make sure cold pack is not in direct contact with specimen.
CPT Code(s)*
88342 x 1 or 88341 x 1 (qualitative IHC) or 88360 x 1 (quantitative/semi-quantitative – manual) or 88361 x 1 (quantitative/semi-quantitative – computer assisted)
Turnaround Time
Global: 48 hours, Tech-Only (stain only): 24 hours
New York Approved
Level of Service
Stain Only

*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.