Objective:To investigate the accuracy and feasibility of applying rapid immunohistochemistry(IHC) with CK5/6 antibodies in prostate biopsy tissues to assist frozen pathology diagnosis.Methods:The data of 41 patients who underwent prostate puncture and frozen tissue rapid IHC with CK5/6 antibody in Beijing Hospital from October 2022 to April 2023 were retrospectively analyzed. The median age of the patients was 76 (69, 79) years old, and the median PSA value was 12.37 (7.07, 26.17) ng/ml.The Prostate Imaging Reporting and Data System (PI-RADS) scores of the target lesions were all ≥3. The PI-RADS score of 9 patients(21.95%) was 3, 15 (36.59%) was 4, and 17(41.46%) was 5. The median diameter of the lesions in the MRI examination was 1.40 (1.09, 2.20) cm.Fourteen lesions (34.14%) were located in the migratory zone, 23 (56.10%) were located in the peripheral zone, and 4 (9.76%) involved both peripheral and migratory zone lesions. Transperineal cognitive fusion targeted combined systematic biopsy was used, and intraoperatively, 1 additional needle was taken from each of the target and non-target areas for frozen pathology section, and hematoxylin eosin(HE) staining and rapid IHC staining with CK5/6 antibody was performed, then the frozen remaining tissue was HE staining and CK5/6 IHC staining. Data such as HE and rapid IHC results of frozen pathology sections and HE and IHC results of routine sections of the frozen remaining tissues, International Society of Urological Pathology (ISUP) grading groupings(GG), and actual diagnostic results of targeted combined systematic puncture were recorded. Using the routine IHC results of the same needle tissue as the gold standard, the sensitivity and positive predictive value of applying rapid IHC frozen pathology to diagnose prostate cancer and the accuracy of its pathological GG were analyzed.Results:Among the 41 patients, a total of 35 cases were diagnosed with prostate cancer(PCa) by HE staining in frozen section of target tissue, with a positivity rate of 85.37%(35/41). Among these, there were 17 cases (48.57%) in ISUP GG 1, 8 cases (22.86%) in GG 2, 4 cases (11.43%) in GG 3, and 6 cases (17.14%) in GG 4 to 5. In addition, a total of 35 cases were diagnosed with PCa by HE staining in frozen remaining section of target tissue, with a positivity rate of 85.37%(35/41). Among these, there were 17 cases (48.57%) in ISUP GG 1, 8 cases (22.86%) in GG 2, 4 cases (11.43%) in GG 3, and 6 cases (17.14%) in GG 4 to 5. The results of rapid IHC of target tissue: 35 cases were negative for CK5/6 expression and 6 cases were positive. The results of routine IHC of target tissue: 35 cases were negative for CK5/6 expression and 6 cases were positive. The results of rapid IHC of non-target tissue: 12 cases were negative for CK5/6 expression and 29 cases were positive. The results of routine IHC of non-target tissue: 12 cases were negative for CK5/6 expression and 29 cases were positive. Thirty-five cases of target tissue rapid IHC diagnosis of PCa were in complete agreement with routine IHC diagnosis, with a false-positive rate of 0, a sensitivity of 100.00% (35/35) and a positive predictive value of 100.00% (35/35). Twelve cases of non-target tissue rapid IHC diagnosis of PCa were in complete agreement with routine IHC diagnosis, with a false-positive rate of 0, a sensitivity of 100.00% (35/35), and a positive predictive value of 100.00% (12/12).Conclusions:The preliminarily study results confirmed that the application of rapid IHC with CK5/6 antibodies in prostate biopsy tissues assisted frozen pathology diagnosis with high accuracy, but the reliability of rapid IHC technology in assisting frozen pathological diagnosis during puncture surgery still needs further validation through large sample size prospective studies.