Androgen receptor immunohistochemistry in genitourinary neoplasms

Androgen receptor (AR) is a recognized immunohistochemical marker of prostate cancer. However, the sensitivity and specificity of AR for prostate cancer in the setting of other genitourinary neoplasms has not been rigorously studied.

We employed tissue microarrays containing prostate carcinomas, urothelial carcinomas, renal cell carcinomas, and testicular neoplasms. Slides were stained immunohistochemically for AR.

Androgen receptor was positive in 95% of prostate carcinomas (n=230), but 19% of invasive urothelial carcinomas of the bladder (n=190) and 33% of non-invasive bladder urothelial carcinomas were also AR positive (N=107). Furthermore, 16% of renal pelvis urothelial carcinomas (n=43) were positive. Of primary renal cell carcinomas, 19% were AR positive (n=307). From a metastatic renal cell carcinoma cohort, 28% of metastases were AR positive (N=126). Six percent of non-teratomatous testicular germ cell tumors stained for AR (n=103).

Our data show that the sensitivity of AR immunohistochemistry for prostate cancer is 94.8%. However, the specificity of AR is only 81.4%, among our cohort of invasive genitourinary tumors. Thus, we find the specificity of AR suboptimal, yet AR may remain useful as a component of an immunostain panel.