Prevalence and Characteristics of Inflammation in Prostate Cancer

Extract

Background: The presence of lymphocytic inflammatory aggregates (LIAs) is a common finding in submitted prostate tissue and frequently not mentioned. Recent studies linked prostate cancer (PCa) to chronic inflammation of prostate and exposure to sexually transmitted diseases, and suggested that viruses may play a role in development of PCa. Another study demonstrated that pathogenesis of prostatic neoplasia (in the PhIP treated rat prostate) proceeds from inflammation to post-inflammatory proliferative atrophy to prostatic intraepithelial neoplasia (PIN). In a previous study, we concluded that presence of chronic inflammation (mainly lymphocytic) in prostate needle biopsy is frequently associated with presence of PCa on same side, even if needle biopsy did not detect PCa. Design: A retrospective analysis of pathology database is conducted at our institution for prostatectomy recorded (January 2012 to January 2013). A total of 30 cases of prostatectomy with diagnosis of PCa are included. Sections from each case that has LIAs are stained with IHC stains: CD3/CD8/CD4/CD20/CD56/CD68. Results: LIAs on H&E-stained slides were found in all cases. No significant number of polymorph nuclear leukocytes (PMNs) or plasma cells was identified. LIAs had a pattern of staining where CD20-positive cells are more packed and at center, while CD3-positive cells were more scattered and toward periphery. IHC staining pattern of T lymphocytes showed a combination of CD4 (67%) and CD8 (33%). CD56 staining was negative in all cases. The CD68 stained cells are more scattered over a larger area surrounding and in background of LIAs. Conclusion: An inflammatory pattern of LIAs with a background of macrophages was identified in all cases. This inflammation did not have PMNs or plasma cells. The IHC staining of LIAs showed a pattern of staining where B lymphocytes are packed at center while T lymphocytes are scattered at periphery. T lymphocytes consist of a combination of both mature T helper cells (CD4) and cytotoxic T cell (CD8). No natural killer (NK) cells were identified with CD56 staining.