Test Catalog

Test ID: PAX8    
PAX8 Immunostain, Technical Component Only

Useful For Suggests clinical disorders or settings where the test may be helpful

Aids in the identification of renal cell carcinomas, as well as papillary thyroid carcinomas and tumors of Mullerian origin

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

PAX8 is a member of the paired box gene (PAX) family of transcription factors involved in kidney cell and thyroid development. PAX8 has been shown to be expressed in a high percentage of renal neoplasms, including both malignant renal cell carcinomas and benign renal tumors (oncocytomas). PAX8 has also been reported to be expressed in ovarian carcinomas.

Interpretation Provides information to assist in interpretation of the test results

This test includes only technical performance of the stain (no pathologist interpretation is performed). Mayo Clinic cannot provide an interpretation of tech only stains outside the context of a pathology consultation. If an interpretation is needed, refer to PATHC / Pathology Consultation for a full diagnostic evaluation or second opinion of the case. All material associated with the case is required. Additional specific stains may be requested as part of the pathology consultation, and will be performed as necessary at the discretion of the Mayo pathologist.


The positive and negative controls are verified as showing appropriate immunoreactivity and documentation is retained at Mayo Clinic Rochester. If a control tissue is not included on the slide, a scanned image of the relevant quality control tissue is available upon request. Contact 855-516-8404.


Interpretation of this test should be performed in the context of the patient's clinical history and other diagnostic tests by a qualified pathologist.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Age of a cut paraffin section can affect immunoreactivity. Stability thresholds vary widely among published literature and are antigen-dependent. Best practice is for paraffin sections to be cut fresh.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Chang A, Brimo F, Montgomery EA, et al: Use of PAX8 and GATA3 in diagnosing sarcomatoid renal cell carcinoma and sarcomatoid urothelial carcinoma. Hum Pathol 2013;44:1563-1568

2. Hu Y, Hartmann A, Stoehr C, et al: PAX8 is expressed in the majority of renal epithelial neoplasms: an immunohistochemical study of 223 cases using a mouse monoclonal antibody. J Clin Pathol 2012;65:254-256

3. Laury AR, Perets R, Piao H, et al: A comprehensive analysis of PAX8 expression in human epithelial tumors. Am J Surg Pathol 2011;35(6):816-826

4. Ozcan A, Shen SS, Hamilton C, et al: PAX8 expression in non-neoplastic tissues, primary tumors, and metastatic tumors: a comprehensive immunohistochemical study. Mod Pathol 2011;24:751-764

5. Tacha D, Qi W, Zhou D, et al: PAX8 mouse monoclonal antibody (BC12) recognizes a restricted epitope and is highly sensitive in renal cell and ovarian cancers but does not cross-react with B cells and tumors of pancreatic origin. Appl Immunohistochem Mol Morphol 2013;21(1):59-63

6. Tacha D, Zhou D, Cheng L, et al: Expression of PAX8 in normal and neoplastic tissues-A comprehensive immunohistochemical study. Appl Immunohistochem Mol Morphol 2011;19(4):293-299