PAX-8 along with PAX-2 are transcription factors (nuclear expression) important in the development of Mullein system, kidney, and thyroid. They both are expressed in normal kidney and most renal neoplasms. PAX-8 expression may also be seen in carcinomas of the lower urinary tract and nephrogenic adenomas. In the study by Ozacan et. al., PAX-8 had better performance characteristics than PAX-2.
PAX-8 is not expressed in cancers from rectum, pituitary, adrenal, colon, prostate, breast, lung, stomach, liver, soft tissue, melanoma, and lymphoma. The rabbit monoclonal PAX-8 antibody shows staining in lymph nodes, pancreas, and stomach/colon neuroendocrine cells. The mouse PAX-8 antibody clone BC12 does not appear to have expression in lymph nodes, pancreas and stomach/colon neuroendocrine cells. (Tacha, D., et. al.) In an experience by Ortiz-Rey, et al., they found PAX-8 to be helpful in differentiated seminal vesicle epithelium from prostate epithelium in needle core biopsies. Sometimes this can be difficult to differentiate from carcinoma, and could be helpful in a panel to differentiate epithelial types.
Ozcan, A., et. al.
|
Tumor Type
|
No.
|
PAX-2
|
PAX-8
|
|
Renal Cell Carcinoma
|
|
|
|
|
Clear Cell
|
95
|
95%
|
97%
|
|
Papillary
|
38
|
76%
|
100%
|
|
Chromophobe
|
25
|
56%
|
88%
|
|
Collecting Duct
|
7
|
43%
|
71%
|
|
Acquired Cystic Kidney
Disease-related RCC
|
8
|
75%
|
100%
|
|
Oncocytoma
|
13
|
54%
|
85%
|
Galley, M.P., et. al.
|
Tumor Type
|
PAX-8 (%)
|
|
Uterine Cervix SCC
|
3%
|
|
Urothelial Carcinoma
|
10%
|
Normal Tissue Expression for PAX-8 (Chan, J.K.C.)
|
Tissue
|
Expression Pattern
|
|
Thyroid
|
Follicular epithelium
|
|
Kidney
|
Tubular epithelium and Bowman capsule lining cells
|
|
Female Genital Tract
|
Ovary – inclusion cysts, rete ovarii, not surface mesothelium
Fallopian Tube – epithelium
Uterus – epithelium
Endocervix – epithelium (weak to moderate staining)
|
|
Male Genital Tract
|
Epithelium from tete testis to ejaculatory duct
|
|
Thymus
|
Thymic epithelium (weak staining)
|
|
Pancreas
|
Islet cells (rabbit polyclonal ab, mouse clone BC12 does not appear to cross react)
|
|
Lymphocytes
|
Subset of lymphoid cells, thought to be due to cross-reactivity with PAX-5 (rabbit polyclonal ab, mouse clone BC12 does not appear to cross react)
|
References:
Shen, SS. “Role of Immunohistochemistry in Diagnosing Renal Neoplams: When Is It Really Useful?”Arch Pathol Lab Med, Vol. 136, April 2012. pp. 410-417.
Al-Ghawi, H., Asojo, O. A., Truong, L. D., Ro, J. Y., Ayala, A. G., & Zhai, Q. J. (2010). Application of Immunohistochemistry to the Diagnosis of Kidney Tumors. Pathology Case Reviews, 15(1), 25–34. doi:10.1097/PCR.0b013e3181d51c70
Ozcan, A., la Roza, de, G., Ro, J. Y., Shen, S. S., & Truong, L. D. (2012). PAX2 and PAX8 expression in primary and metastatic renal tumors: a comprehensive comparison. Archives of Pathology & Laboratory Medicine, 136(12), 1541–1551. doi:10.5858/arpa.2012-0072-OA
Chan, J. K. C. (2013). Newly Available Antibodies With Practical Applications in Surgical Pathology. International Journal of Surgical Pathology, 21(6), 553–572. doi:10.1177/1066896913507601
Gailey, M. P., & Bellizzi, A. M. (2013). Immunohistochemistry for the novel markers glypican 3, PAX8, and p40 (ΔNp63) in squamous cell and urothelial carcinoma. American Journal of Clinical Pathology, 140(6), 872–880. doi:10.1309/AJCP4NSKW5TLGTDS
Tacha, D., Qi, W., Zhou, D., Bremer, R., & Cheng, L. (2013). 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. Applied Immunohistochemistry & Molecular Morphology : AIMM / Official Publication of the Society for Applied Immunohistochemistry, 21(1), 59–63. doi:10.1097/PAI.0b013e318257cc1c
Ortiz-Rey – PAX8 AIMM editorial