Immunohistochemistry contribution to the diagnosis of prostate cancer

Abstract

Introduction: Efforts for the identification of prostate cancer in the initial clinical and pathological stages led to an increase in the number of biopsies, sometimes making the histological diagnosis of adenocarcinoma difficult. This is due to the presence of minimal carcinoma or atypical glands suspicious for carcinoma, also known as atypical small acinar proliferation (ASAP). In these cases, the use of immunohistochemistry (IHC) has become a common practice in laboratories of pathology. Objectives: The aims of this study were to assess the incidence of diagnoses of ASAP and minimal adenocarcinoma in two laboratories of pathology and to evaluate the contribution of IHC and repeat biopsy to the diagnosis of prostate cancer. Methods: We reviewed 641 sets of modified sextant needle biopsies of the prostate performed in two laboratories of pathology between January 2005 and December 2010. IHC using 34βE12 and p63 antibodies was performed on 35 of 73 (11.38%) cases diagnosed as ASAP and on 7 (1.1%) cases diagnosed as minimal adenocarcinoma. Results: The incidence of ASAP diagnosis was 11.38% (n = 73). IHC was performed in 35 of the 73 ASAP cases and provided conclusive results in 31 cases (88.57%), resulting in a fnal diagnosis of adenocarcinoma in 19 patients (54.28%), benign lesions in 12 patients (34 28%); only 4 (11.42%) were inconclusive. Conclusion: The results suggest that IHC should be routinely used in evaluation of borderline biopsies and in ASAP cases. IHC strongly contributes to the diagnosis of prostate cancer.