Role of Two Antibodies Panel High Molecular Weight Cytokeratin and Alpha-Methylacyl-CoA Racemase in Diagnosing Prostatic Lesions: A Cross-sectional Study

Abstract

Introduction: Prostatic diseases cause significant morbidity and mortality. Although histopathological examination is the gold standard for diagnosing prostatic lesions but diagnosis may be challenging in the presence of benign mimickers or a very small focus of malignancy. Immunohistochemical aid to morphology helps in making a timely and accurate diagnosis. Aim: This study was done to evaluate the role of two antibodies panel High Molecular Weight Cytokeratin (HMWCK) and Alpha-Methylacyl-CoA Racemase (AMACR) in improving the diagnostic accuracy of prostatic lesions. Materials and Methods: This was an observational cross-sectional study conducted in the Department of Pathology, Shri Guru Ram Rai Institute of Medical and Health Sciences (SGRRIM and HS), Dehradun, Uttarakhand, India, from May 2019 to October 2020. Haemotoxylin and Eosin (H&E) stained sections of prostatic biopsies were classified into benign and malignant. Amongst malignant lesions, prostatic adenocarcinomas were graded according to Gleason’s grading system and Gleason’s scores were noted. One section from each was subjected to AMACR and HMWCK antibody tests. HMWCK was interpreted as negative/positive and continuous/discontinuous. For AMACR, both location and intensity of stain was observed. The parameters studied were Gleason’s score, group grade, expression of HMWCK and AMACR. Categorical data was presented in form of frequency and percentage. Independent t-test, Yates Chi-square test were used. Data was entered in Microsoft (MS) Excel sheet and analysis was done using CRAN R 2.1. Results: Total of 80 prostatic biopsies were taken, 24 were malignant and 55 were benign and one was Benign Prostatic Hyperplasia (BPH) with a focus suspicious for malignancy showing atypical small acinar proliferation on histopathological examination. The mean age of non neoplastic cases was 67.68±8.56 years, while that of neoplastic lesions was 75.41±9.34 years. Amongst benign, 56.3% (31/55) cases were BPH, 43.6% (24/55) cases were BPH with associated lesions which included 62.5% (15/24) cases of BPH with non specific prostatitis; 29.2% (7/24) cases of BPH with adenosis and 8.3% (02/24) cases of BPH with basal cell hyperplasia. Of malignant cases, 24 cases were of adenocarcinoma with maximum cases having Gleason’s score 9 (11/24;45.8%) and Group grade V (18/24;75%). The sensitivity, specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV) of HMWCK and AMACR were calculated using histopathology as the gold standard. Conclusion: Although histopathology is the gold standard in prostatic biopsies but immunohistochemistry is additional diagnostic aid in confirmation of diagnosis. Immunohistochemistry not only confirms the histological diagnosis but is of great help in challenging cases. It has markedly increased the diagnostic accuracy.

Keywords

• benign prostatic hyperplasia
• immunohistochemistry
• prostate cancer