Diagnostic value of a combined AMACR, P63, and ERG immunohistochemical panel in distinguishing benign from malignant prostate lesions

Objectives: Diagnosing prostate cancer is difficult because its histological traits often overlap with those of benign conditions. Alpha-methylacyl-CoA racemase (AMACR), tumor protein 63 (P63), and erythroblast transformation-specific-related gene (ERG) are commonly utilized immunohistochemical markers. The triple-marker panel showed a marginal incremental diagnostic benefit over AMACR alone and may improve diagnostic confidence in selected difficult cases. Methods: The specimens were immuno-stained with antibodies targeting AMACR, P63, and ERG. Sensitivity and specificity for AMACR, P63, and ERG were determined. Hematoxylin and eosin staining is the reference standard as it is a rapid, cost-effective diagnostic tool offering excellent morphological detail, allowing accurate identification of architectural and cellular features for diagnosis, grading, and prognosis. Results: Among the evaluated specimens, 128 (66%) showed benign prostatic hyperplasia, while 66 (34%) showed prostatic adenocarcinoma on histopathological examination (HPE). Perineural invasion occurred in 32 (48.5%) of malignant cases. AMACR immunohistochemical expression was found in 54 (82%) of malignant cases and 24 (18.7%) of benign cases. P63 expression was present in 122 (95.3%) benign lesions. ERG expression was observed in 23 (34.8%) of malignant cases. The diagnostic accuracy of AMACR, P63, and ERG was 98.3%, 89.7%, and 86%, respectively. The triple-marker panel (AMACR + P63 + ERG) achieved 97% sensitivity, 99.2% specificity, and 98.5% diagnostic accuracy, indicating an incremental diagnostic gain in prostate biopsy specimens. Conclusion: The triple-marker panel yielded a diagnostic accuracy rate of 98.5%, despite ERG’s comparatively lower sensitivity. The combined use of AMACR, P63, and ERG may be considered in selected diagnostically challenging cases.