PCSD1 xenograft tumors expressed human prostate PSA and human AR. A. RNA was extracted from secondary transplant sub-cutaneous xenograft tumors (Passage 1, P1) and used for RT-PCR analysis of human prostate specific antigen (PSA) and human androgen receptor (AR). Human PSA and human AR-specific primers were used for PCR amplification of cDNA synthesized with reverse transcriptase (RT+) or without (RT-) and confirmed by sequencing of correctly sized bands. Human GAPDH-specific primers were used as an internal control. Human PSA and AR were expressed in the PCSD1 xenograft tumor and the human prostate cancer cell line, LAPC4, but not in the human chronic myelogenous leukemia (CML) cell line, K562. RNA from mouse spleen, bone marrow and liver did not express human PSA or AR. B. Immunohistochemical analysis showed human PSA protein expression in PCSD1 xenograft tumors. Images show paraffin embedded (PPFE) sub-cutaneous PCSD1 secondary transplant xenograft sections stained with IgG isotype negative control or human PSA-specific antibody. (C) Upper panels show H and E stained intra-femoral PCSD1 secondary transplant xenograft cryosections at 10× and 20× magnification. Middle panels show cryosections from the left, un-injected, contralateral femurs immunostained with human PSA-specific antibody at 10× and 40×. Arrows show red blood cells in bone marrow. Lower panels show cryosections from secondary intra-femoral transplants of PCSD1 immunostained with anti-PSA. Arrows point to human PSA positive (+) prostate cancer cells.