Of 61 cases of PSCC, 51% (31/61) demonstrated increased AR gene copy number (FISH+), 54% (33/61) were positive for TMPRSS2-ERG gene fusion, and 38% (23/61) showed AR protein expression.     ///    "Of the 31 AR FISH+ cases, 23 also showed TMPRSS2-ERG gene fusion, and 16 expressed AR protein. "    ///    "Statistically significant correlations were observed between AR gene copy number or AR protein expression and TMPRSS2-ERG gene fusion (P?=?0.001 and P?=?0.03, respectively). "    ///    The TMPRSS2-ERG gene rearrangement is highly specific for prostate cancer and shared by PSCC.     ///    Sixty-one cases of PSCC were examined for AR gene copy number and TMPRSS2-ERG rearrangement by fluorescence in situ hybridization (FISH) and AR protein expression by immunohistochemistry.     ///    "however, the role of androgen receptor (AR) gene alterations and interaction with TMPRSS2-ERG rearrangement are incompletely understood in PSCC. "    ///    Increased androgen receptor gene copy number is associated with TMPRSS2-ERG rearrangement in prostatic small cell carcinoma..     ///    "In summary, high AR gene copy number emerges during the development of PSCC, often in association with TMPRSS2-ERG rearrangement. "