Single Agent Temsirolimus (Torisel®) in Chemotherapy-naïve Castration-Resistant Prostate Cancer Patients

Inclusion Criteria: 1. Understand and voluntarily sign an informed consent form. 2. Age 18 years at the time of signing the informed consent form. 3. Able to adhere to the study visit schedule and other protocol requirements. 4. Documented prostate cancer regardless of the Gleason score 5. Patients should be considered hormone refractory and castration-resistant. They must fail LHRH analogues, and anti-androgen withdrawal trial. Failure is confirmed by an increase in PSA value of 10% or more than the value immediately before. 6. Patients must have measurable disease either biochemically (using PSA) and/or using the Response Evaluation Criteria in Solid Tumors (RECIST) criteria for visceral organ involvement and/or bone disease. If there is no disease to follow on scans a PSA value of at least 5 ng per milliliter needs to be present at baseline to be evaluated for PSA response. 7. Eastern Cooperative Oncology Group (ECOG) Performance Status of 2 or less. 8. Adequate liver function tests with ALT/AST being \< 3x normal, total bilirubin of 1.5 or less, and adequate renal function measured by a creatinine of 2.0 mg/dl or less. Alkaline phosphatase values are never exclusion criteria if it is deemed related to bone metastases. 9. Patients need to have adequate bone marrow function. * absolute neutrophil count (ANC) of 1000 or above, * Hgb of 9.0 g/dl or above, * Platelets of 100,000 or above. If other causes are affecting plts counts such as autoimmune disorders, patients are allowed on study. Patients with inadequate bone marrow function that is deemed related to bone marrow involvement with prostate cancer (cytopenias are due to extensive marrow infiltration with prostate cancer) are allowed at the investigator's discretion. 10. Patients with other malignancies are allowed as long as there is no evidence of the other malignancy present at entry time, and it has been 3 years or more since the treatment for the other disorder was completed. Patients with non-melanoma skin cancers are allowed to participate in the study. 11. Investigational therapy such as vaccines, immunotherapy, and oral targeted agents are allowed on this study as long as their last exposure was 4 weeks prior to study entry. These agents are not considered an exclusion criteria as they are not considered standard chemotherapy. 12. Patients with known bone metastases are allowed to receive intravenous bisphosphonates such as aredia or zometa. Patients on oral bisphosphonates are also allowed. 13. All study participants are encouraged to continue androgen deprivation with an LHRH analogue. 14. Patients must agree to use a latex condom during sexual contact with a female of childbearing potential, even if they have had a successful vasectomy and despite the fact that they are on androgen deprivation. 15. Last treatment for prostate cancer should be at least 4 weeks ago Exclusion Criteria: 1. Prior systemic chemotherapy for castration Resistant Prostate Cancer (CRPC) 2. Prior exposure to temsirolimus (TEM) 3. Known HIV positive status or infectious hepatitis, type A, B, or C. 4. Known brain metastases. 5. Steroids are allowed concomitantly ONLY IF they are taken for another chronic medical condition (Such as chronic obstructive pulmonary disease , Multiple sclerosis…etc) 6. Any serious medical condition, laboratory abnormality, or psychiatric illness that would prevent the subject from signing and understanding the informed consent form. 7. Any condition, including the presence of laboratory abnormalities, which places the subject at unacceptable risk if he were to participate in the study or confounds the ability to interpret data from the study. 8. Use of any other experimental drug or therapy within 28 days of baseline.