Study to Evaluate HER2-neu Expression in Different Histopathological Grades of Prostatic Carcinoma in a Tertiary Care Centre, Bareilly

Abstract

Introduction: Prostate cancer is the second most common neoplasm among men around the world. Two routinely used immunocytochemical markers for prostatic epithelium are Prostatic Acid Phosphatase (PAP) and Prostatic Specific Antigen (PSA). Various other markers like Prostate-Specific Membrane Antigen (PSMA), androgen and progesterone receptors, HER2- neu, low molecular weight keratin, etc., are also used. HER2-neu overexpression has been implicated in tumorigenesis and has been correlated with a poor prognosis for patients with breast cancer, ovarian cancer, and gastric cancer. Use of Trastuzumab for the treatment of breast carcinoma has improved prognosis in HER2-neu positive cases. Recent studies have suggested the correlation of HER2-neu overexpression with higher grades of prostate cancer. Aim: To study HER2-neu expression in different histopathological grades of prostatic carcinoma. Materials and Methods: A prospective study was carried out on 41 histopathologically proven cases of prostatic carcinoma in Pathology Department of SRMSIMS, Bareilly over a period of one year and six months (November 2017 to April 2019). Gleason grading and HER2-neu Immunohistochemistry was applied on every case and then correlated. Statistical tests were applied, statistical software Statistical Package for the Social Sciences (SPSS) version 21. Results: A 92.7% (38/41) cases were reported as Prostatic Adenocarcinoma of Non-Mucinous type. Total of 42.5% (17/40) were grouped under Grade group 5, 27.5% (11/40) cases under Grade group 3 and 10% (4/40) under Grade groups 1,2 and 4 each. Out of total, 14.6% (6/41) cases were considered as positive and 80.5% (33/41) cases were considered as negative for HER2-neu expression and 4.9% (2/41) cases were considered as equivocal (Fluorescence In Situ Hybridization (FISH) conformation required). In cases with positive HER2-neu expression, mean group grade was calculated to be 4.83±0.40 and in patients with negative HER2-neu expression, it was 3.38±1.40 (it was calculated to find correlation between group grade and HER2-neu expression). There was a significant statistical difference (p=0.00003668) found between the Gleason Group Grade in HER2-neu positive and negative patients as HER2-neu positivity is seen in higher group grades. One case was reported as neuroendocrine carcinoma in which Gleason grading was not done. Conclusion: Compared to low Gleason Group Grade carcinoma, higher percentage of HER2-neu expression was seen in high Gleason Group grade carcinoma.

Keywords

• prostatic adenocarcinoma
• prostatic specific antigen
• trastuzumab