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Test Name:PIT-1 by IHC
Test Number:12376 - Technical only; 12379 - Technical & Interpretation
Collect:Formalin-fixed, paraffin embedded (FFPE) tissue block
Container:FFPE tissue block
Processing:Submit processed tissue block or tissue section mounted on a charged, unstained slide
Transport/Stability:Ambient (preferred)
Alternate Names:IHC
Performing Lab:AHL - Immunohistochemistry
Days Set Up:Mo - Fr
Expected TAT:1 - 2 days
Ref. Ranges:If requested, an interpretive report will be provided
All IHC stains will include a positive control tissue
Processing Details:

  • The PIT-1 gene encodes a transcription factor involved in anterior pituitary development, where it is expressed in cell types responsible for prolactin, growth hormone and beta thyroid stimulating hormone (beta-TSH, also known as beta-thyrotropin) production
  • The antibody to the protein Pit-1 reacts with this transcription factor in normal adenohypophysis and in pituitary adenomas, which show development along this line
  • Hence, pituitary adenomas that produce prolactin, growth hormone or beta-TSH (or combinations thereof), are expected to be positive using this stain1, 2
Staining pattern:
  • Strong nuclear staining is observed within lactotrophs, somatotrophs, mammosomatotrophs, thyrotrophs and pituitary adenomas that develop along these lines of differentiation
  • Pit-1 immunostain is useful for diagnosis of the family of pituitary adenomas that display development along the Prolactin-Growth Hormone-TSH spectrum
  • It is also present within normal anterior pituitary gland, so the presence of pituitary adenoma must be confirmed on H&E stains (occasionally with the support of ancillary stains such as reticulin stains for normal adenohypophyseal architecture).
Note: Pit-1 should generally be used in conjunction with other pituitary stains to help subtype pituitary adenomas.

  1. Friend KE, Chiou YK, Laws ER, Jr., Lopes MB, Shupnik MA. Pit-1 messenger ribonucleic acid is differentially expressed in human pituitary adenomas. J Clin Endocrinol Metab. 1993;77(5):1281-6.
  2. Pellegrini I, Barlier A, Gunz G, Figarella-Branger D, Enjalbert A, Grisoli F, et al. Pit-1 gene expression in the human pituitary and pituitary adenomas. J Clin Endocrinol Metab. 1994;79(1):189-96.

Method:Immunohistochemical staining
Microscopic examination
CPT Codes:88342 - 1st stain
88341 - each additional stain
Date Created:08/07/2017
Revised Date:10/19/2018