SYP and small cell carcinoma: However, with the exception of highly aggressive neuroendocrine/small cell carcinomas, it remains debatable if increased number of neuroendocrine cells, as defined by their expression of neuroendocrine markers, such as synaptophysin and calcitonin gene-related peptide, are essential for the accelerated progression of pre-castrate prostate adenocarcinoma6,51,52.