“…The earlier report by Graham et al (1993) used ovalbumin with a goat secondary antibody, whereas, in the present study, we employed 20% sheep serum along with a sheep secondary antibody. Whether this would account for the differences seen is not clear, but it is well established that the use of blocking and secondary sera from the same species produces less non-specific staining (Bancroft and Cook, 1994 (Harper and Thoenen, 1980;Shikata et al, 1984;MacGrogan et al, 1990 (Allen et al, 1995). Although the presence of these cells may not be a prognosticator, there is evidence that as prostate adenocarcinomas dedifferentiate (Allen et al, 1995), progress (Aprikian et al, 1994) and become androgen independent (Berner et al, 1993), they contain a higher portion of neuroendocrine elements.…”