The goal of this clinical research trial is to study the effects of the FDA-approved drug, temsirolimus, using a new type of clinical study design called a "Phase 0." This type of study may be able to predict if a drug can affect cancer and may be able to prevent potentially useful study drugs from being discarded before they are fully tested.

The purpose of the study is not to treat the cancer, but to help improve general cancer treatment knowledge.

Study Drug:

Temsirolimus is designed to block the growth of cancer cells, which may cause the cancer cells to die.

Study Drug Administration:

If you are found to be eligible to take part in this study, you will receive temsirolimus by vein over about 60 minutes on Day 1.

You will be assigned to a dose level of temsirolimus based on when you join this study. Up to 5 dose levels of temsirolimus will be tested. Up to 3 participants will be enrolled at each dose level. The first group of participants will receive the lowest dose level. Each new group will receive a higher dose than the group before it, until the drug is found to affect the enzyme that was tested for at screening.

Study Visits:

At each study visit, you will be asked about any drugs you may be taking and about any side effects you may be having.

On Day 1:

-Blood (about 2 teaspoons each time) will be drawn before you receive the study drug and 5 times over the 24 hours after you receive the study drug for pharmacokinetic (PK) testing. PK testing measures the amount of study drug in the body at different time points.

Blood (about 4 teaspoons each time) will be drawn for pharmacodynamic (PD) testing. PD testing measures how the level of study drug in your body may affect the disease. This blood will be drawn at 1 or more of the following times, but if the doctor thinks it is needed, blood will be drawn at 2 or all 3 of the following times:

• At 4 hours (+/- 2 hours) after the dose
• At 24 hours (+/- 3 hours) after the dose
• At 72 hours (+/- 24 hours) after the dose

After the blood for PD testing has been tested and the tests show that the study drug may be causing changes to the tumor cells in at least 2 out of 3 participants, future participants will have tumor tissue collected before and after dosing for testing. Leftover tissue from an earlier biopsy can be used instead of a fresh biopsy before dosing, if it is available.

Length of Study:

You will be on study for up to 4 days. You will be taken off study early if you have intolerable side effects.

Because it takes 4 days for temsirolimus to be completely processed by the body, you will not be able to begin receiving drugs in any other study until 4 days after the dose.

This is an investigational study. Temsirolimus is FDA approved and commercially available for the treatment of advanced renal cancer. Its use in other types of cancer is investigational.

Up to 30 patients will take part in this study. All will be enrolled at MD Anderson.

Inclusion Criteria:

1. Patients with advanced or metastatic cancer, preferably with tumor easily accessible for biopsy.
2. Patients should be at least four weeks or 5 half lives from the last day of chemotherapy, antibody or other biological therapy, whichever is shorter.
3. Patients should preferably be undergoing screening for 2007-0668, 2008-0384, 2008-0425, and 2008-0827 (currently active Phase I trials involving temsirolimus). However, patients may also be allowed on protocol if they are undergoing screening for any study.

Exclusion Criteria:

1. Pregnant or lactating women.
2. Patients with a known hypersensitivity to any of the components or metabolites of the drug products.
3. Patients with a known bleeding diathesis which would prevent safely obtaining a biopsy if a biopsy is indicated.
4. Patients who are less than 18 years of age.