Quick Score and H-Score Assessment of P504s (AMACR) Expression in Renal Cell Carcinoma (RCC) and Relation with Histologic Grade

Background and Aims: P504S (AMACR) is a mitochondrial enzyme expressed in renal cell carcinoma. Some of immunohistochemical markers in renal cell tumors are independent prognostic factor and show relation with histologic grading. AMACR expression increases with higher histological grading in different tumors; however, in RCC it is not obvious. In this study, we tried to investigate if any relation existed between nuclear grading in renal cell carcinoma and P504S. Materials & Methods: Fort five cases of formalin fixed paraffin embedded tissue of renal cell carcinoma with different nuclear grades were selected and immunostained using primary antibody to P504s and quantified with H-Score, multiplicative (Mqs) and Additive quick score (Aqs). Results: P504S was positive in 37 out of 45 (82%) cases. (Mean ± SD) of H-Score: grade I =182±44. II=218±161, III=215±55, IV=190. Mean ± SD of Add quick score: grade I= 6.6± 1.8, II= 7.24±1.4, III= 7.78±1.2, IV= 8. Mean ± SD of Multi quick score: grade I= 9± 5.6, II= 11.38±5, III =12.89±4.7, IV= 12. (Aqs Vs H- Score: r = 0.701, P < 0.007), (Mqs Vs H-Score: r = 0.808, P < 0.001) Conclusion: P504S is one of the important immunohistochemical markers in primary and metastatic RCC. Our results show that there is no statistically correlation between histological grade of RCC and AMACR staining in semi – quantitative measurement. We suggest AMACR staining to be used as a diagnostic immunohistochemical marker in conjunction with other markers in differential diagnosis of metastatic renal papillary and even clear cell carcinoma.