Expression of nectin-4 in prostate cancer.

Objective: Nectin-4 is a transmembrane protein belonging to the nectin family of immunoglobulin-like molecules which is found in the placenta and trachea under physiological conditions and its expression has been shown in many cancer types. We aimed to investigate for the 1^st time nectin-4 expression in human prostate cancer tissues.

Methods: We retrospectively analyzed the prostate pathology specimens of 82 patients who underwent initial transrectal ultrasound-guided prostate biopsy or transurethral prostate resection and were found to have atypical small acinar proliferation (ASAP) and incidentally prostate cancer. Tissue samples with prostatic cancer were used as a control for alpha-methylacyl-CoA racemase (AMACR), and benign prostatic glands in the same tissue provided the negative control. The intensity and extent of nectin-4 expression were determined microscopically using the histochemical scoring system which was defined as the product of the staining intensity (score: 0-3) and percentage of stained cells (0-100) at a given intensity.

Results: We conducted immunohistochemical analysis of nectin-4 and AMACR expression in all 82 samples. While AMACR expression was positive in prostate cancer tissues with a GS of <7 (n=24, 100%), 7 (n=18, 100%), and ≥8 (n=15, 100%), it was negative in all ASAP samples (n=25, 100%) (p<0.001). Nectin-4 expression was not detected in any of the GS <7, GS 7, or GS ≥8 samples but was found in benign prostatic gland tissues and all 25 (100%) ASAP samples (p<0.001).

Conclusion: We found that nectin-4 was not expressed in prostate cancer tissues but was expressed in ASAP-and benign prostate gland containing tissues. We believe that prospective studies with more patients and samples including radical prostatectomy materials will reveal the relationship between nectin-4 and prostate cancer more clearly.