Diagnosis of anal or small bowel carcinoma. Previously identified small cell neuroendocrine tumours or pure small cell carcinoma of the prostate, based on a prior biopsy of the prostate. Pathology consistent with majority of specimen having small cell carcinoma of the prostate (prostate cancer with neuroendocrine features is acceptable) Pathologic findings consistent with small-cell or neuroendocrine carcinoma of the prostate Histologic diagnosis of prostate adenocarcinoma\r\n* Pure small cell carcinoma will be excluded; however, component of neuroendocrine /small cell differentiation will be allowed provided that adenocarcinoma constitutes majority of the tissue specimen Patients must have histologically or cytologically confirmed adenocarcinoma of the prostate with no histological variants (such as small cell, sarcomatoid, pure ductal cancer, transitional cell carcinoma). Pathologically–confirmed small cell carcinoma of any primary site Diagnosis of germ cell tumor, small cell carcinoma or hematologic malignancy Histologic evidence of neuroendocrine or small cell carcinoma of the prostate Patients with histologic evidence of small cell carcinoma of the prostate will not be eligible Have a pathological diagnosis of prostate carcinoma Patients with histologic evidence of small cell carcinoma of the prostate will not be eligible Pathological finding consistent with small cell carcinoma of the prostate Pathological finding consistent with small cell, neuroendocrine carcinoma of the prostate or any other histology different than adenocarcinoma Diagnosis of anal or small bowel carcinoma. Patients with neuroendocrine or small cell carcinoma of the prostate Pathology consistent with majority of specimen having small cell carcinoma of the prostate (prostate cancer with other neuroendocrine features is acceptable) History of small-cell or neuroendocrine prostate carcinoma Pathological finding consistent with small cell, ductal or neuroendocrine carcinoma of the prostate Transitional cell, small cell, or squamous cell carcinoma of the prostate Small cell or neuroendocrine carcinoma of the prostate Pathology consistent with small cell carcinoma of the prostate Pathological finding consistent with small cell carcinoma of the prostate Pathological finding consistent with small cell carcinoma of the prostate Pathologic finding consistent with small cell carcinoma of the prostate Diagnosis of anal or small bowel carcinoma. Pathological finding consistent with small cell carcinoma of the prostate Small cell carcinoma of the prostate Have histologically confirmed carcinoma of the prostate that is metastatic or otherwise incurable, and a BMI defined as obese (i.e. > 30 kg/m^2); any histologic variant is acceptable other than small cell carcinoma Small cell prostate cancer Patients with tumors that have a component of small cell carcinoma Pathological finding consistent with small cell carcinoma of the prostate. Patients with variant histologies (e.g., ductal or small cell carcinoma) Pure small cell carcinoma of the prostate or any mixed histology cancer of the prostate (eg: neuroendocrine) that contains < 50% adenocarcinoma, as observed on biopsy obtained at the time of diagnosis or on any subsequent biopsies Prior pathology consistent with small cell carcinoma or prostate cancer with predominantly neuroendocrine differentiation Patients with histologic evidence of small cell carcinoma of the prostate will not be eligible Patients with histologic evidence of small cell carcinoma of the prostate will not be eligible Small cell carcinoma of the prostate Have a pathological diagnosis of prostate carcinoma Pure small cell carcinoma of the prostate History of neuroendocrine variants of prostate cancer, including small cell carcinoma of the prostate