DIAGNOSTIC UTILITY OF AMACR EXPRESSION TO DIFFERENTIATE PROSTATE CARCINOMA FROM BENIGN HYPERPLASIA OF PROSTATE- A HOSPITAL BASED CROSS-SECTIONAL STUDY.

Corresponding Author:
Dr. Manas Talukdar,
10/1, Girish Ghosh Street,
Kolkata-700108, West Bengal,
India.
E-mail: talukdarmanas09@gmail.com

ABSTRACT

BACKGROUND

Prostatic carcinoma and Nodular Hyperplasia of Prostate (NHP) account for more than 90% of all prostatic diseases. Also, early symptoms of NHP and prostatic cancers are overlapping. However, the final diagnosis is always based on histopathological examination. Currently Trans-rectal ultrasound-guided core biopsy of prostate is the recommended modality of invasive investigation to rule out cancer in suspected cases. However, the lack of a prostate cancer–specific marker, which can be utilized in conjunction with routine histologic examination, remains a limitation. Few literatures have demonstrated the diagnostic usefulness of alpha-methyl-acyl-CoA-racemase (AMACR) in the detection of prostate cancer. We wanted to find out the sensitivity and specificity of this comparatively new marker and its usefulness in differentiating the benign and malignant lesions of prostate.

METHODS

All the core biopsies sent to the Department of Pathology from July 2016 to August 2018 were utilised in this observational cross-sectional study. Only the biopsy reports which could be confirmed by routine H&E stain were included and reports having suspicious or ambiguous diagnosis by routine H&E stain were excluded from the study for further assessment by immunohistochemistry (IHC) marker under evaluation. For IHC, primary antibody was ‘Rabbit Monoclonal Antibody’ to AMACR. The AMACR staining was graded negative, weak or mild (weak non granular cytoplasmic stain), moderate (granular intensity with weak to moderate intensity), and strong (granular staining with strong intensity).

RESULTS

Out of a total of 106 cases, 68 cases (64.15%) had confirmed diagnosis of prostatic adenocarcinoma and rest 38 cases (35.85%) had confirmed diagnosis of benign hyperplasia of prostate by routine H & E method. Out of the total of 68 cases of prostatic adenocarcinoma, 60 cases (88.23%) show strong or moderate positive expression of AMACR in neoplastic glands while rest 8 cases (11.77%) show weak or negative expression of AMACR. Out of the total of 38 benign cases, only 2 cases (5.26%) show false positive expression of AMACR. Sensitivity and specificity of this IHC marker came out to be 88.24% and 94.74% respectively.

CONCLUSIONS

The present study proves that AMACR immunostaining has a very high specificity for diagnosis of prostate adenocarcinoma, but its sensitivity is slightly lower. Careful evaluation of morphologic pattern and combination with basal cell marker with AMACR immunostaining might be more useful for exclusion of prostate cancer in needle biopsy specimen.