225 Utility of PAX8 and PAX2 in Renal and Urothelial Cancers; Is PAX2 Necessary?. (11th January 2018)

• Record Type: Journal Article
• Authors: Raza, Roshan; Matloob, Ammar; Mahabir, Roshan; Modica, Ippolito
• Is Part Of: American journal of clinical pathology. Volume 149(2018)Supplement 1
• Page Start: S96
• Page End: S96
• Publication Date: 2018-01-11
• Subjects: Diagnosis, Laboratory -- Periodicals; Pathology -- Periodicals; 616.07
• DOI: 10.1093/ajcp/aqx123.224
• Languages: English
• ISSNs: 0002-9173

Abstract

Abstract: Introduction: PAX2 and PAX8 transcription factors are known to be expressed by several renal neoplasms, and immunostains for one or both are usually added in their diagnostic panel. Objective: To evaluate the relative diagnostic utility of PAX2 and PAX8. Material and Methods: Biopsy and excision specimens of primary and metastatic renal and urothelial neoplasms with available PAX2 and PAX8 immunostains were retrospectively searched (from January 2010 to March 2017) from three hospitals. Results: A total of 23 tumor (16 primary, seven metastatic) specimens reporting both PAX8 and PAX2 stains in the diagnostic work-up were identified. Within the primary neoplasms, the overall PAX8 and PAX2 expression was seen in 14 of 16 (87.5%) vs four of 16 (25.0%) tumors with two of two (100%) vs one of two (50%) for renal cell carcinoma (RCC; clear cell and papillary), four of six (66.0%) vs none of six (0.0%) for RCC-chromophobe type, five of five (100.0%) vs two of five (40.0%) for oncocytomas, and two of three (66.6%) vs one of three (33.3%) for adenocarcinoma of bladder. Within the metastatic neoplasms, the overall PAX8 vs PAX2 expression was seen in five of seven (71.4%) vs two of seven (28.6%) tumors with four of four (100.0%) vs two of four (50.0%) for clear cell RCC, and one of one (100.0%) vs none of one (0.0%) for medullary collecting duct carcinoma. Both markers were negative for metastatic urothelial carcinoma (0/2). PAX8 was positive in all the metastatic RCC (5/5; 100%) whereas PAX2 was positive in only two of five (40.0%). Conclusions: Both PAX8 and PAX2 are useful markers for diagnosis of primary and metastatic renal neoplasms of variable histologic types. However, PAX8 appears to be more sensitive in malignant cells with more intense staining. Comparatively, PAX2 delivers limited diagnostic yield.