Immunohistochemical Study of Tissue Expression of Nucleophosmin Protein and its association with histopathological parameters in Prostatic Carcinoma in Suez Canal University Hospital

Background: Prostate cancer is the second most common cancer in males. Nucleophosmin (NPM1) is a multifunctional nucleolar protein that plays a role in many cellular processes and in the development of several types of cancer, including prostate cancer Aim: To investigate the immunohistochemical expression of NPM1 Protein in prostatic carcinoma (PCa) tissues and determine its association with the histopathological parameters of PCa. Subjects and Methods: The current work is a cross-sectional descriptive study, conducted in the pathology laboratory of Suez Canal University Hospital on 30 PCa specimens. The specimens included 25 TRUS needle biopsies, 3 prostatectomies and 2 TURP. They were gathered by convenience sampling from records and formalin fixed paraffin embedded tissue blocks during the interval between 2013 and 2019. NPM1 expression was assessed in PCa tissues using immunohistochemistry. Results: NPM1 expression showed nuclear positivity in luminal prostatic epithelial cells in all studied PCa specimens, and the median percentage of expression was 90%. Moreover, strong NPM1 expressions were found in 22 specimens that included 19TRUS needle biopsies, 2 prostatectomies and 1TURP. Moderate expressions were found in only 8 specimens. NPM1 expression showed a weak positive correlation with patients' age (r=0.103) and Gleason Grade (r=0.142). NPM1 expression showed a non-statistically significant association with patients' age, specimen characteristics, prostatic adenocarcinoma growth patterns, Gleason Grade, comedo necrosis, lymphovascular and perineural invasion (p-value <0.05). Conclusions: NPM1 is a potential immunohistochemical marker that may be added to the immunohistochemical diagnostic panel of prostatic carcinoma.