Expression of paired Box-2 gene product in renal tumors as a diagnostic immunomarker

Objective: This study was aimed at evaluating the usefulness of paired box-2 gene (PAX-2) in the diagnosis of renal tumors. Materials and Methods: This study included 60 renal tumors. The newly prepared hematoxylin and eosin stained slides of all cases were evaluated and the diagnoses were confirmed or revised for each tumor according to the 2004 World Health Organization classification of renal tumors. Representative and consecutive sections of each tumor were submitted for anti-PAX-2 antibody immunohistochemistry. The pattern of staining (nuclear or cytoplasmic) was also noted. PAX-2 expression in tumors was correlated with low- and high-nuclear grades (Fuhrman nuclear grades). Results: The 45/60 (75%) cases showed PAX-2 nuclear immunoexpression. The frequency of positivity in renal tumors was seen in 29/34 (85.5%) and 12/15 (80%) cases of clear cell RC, papillary RCC, respectively. The PAX-2 was positive in 20/45 cases for score 1+. The 16/45 cases were categorized into score 2+, and 9/45 cases were categorized into score 3+. Conclusion: PAX-2 is a diagnostically useful marker for primary renal tumors and is inversely proportion to the grades of the renal tumor