DISEASE CHARACTERISTICS:

• Histologically confirmed malignancy, including any of the following types:

  • Renal cell
  • Endometrial
  • Breast
  • Small cell lung carcinoma
  • Lymphoma
• Metastatic or unresectable disease for which standard curative or palliative measures do not exist or are no longer effective
• Measurable disease according to RECIST criteria
• No unstable primary CNS tumors or metastases

PATIENT CHARACTERISTICS:

Inclusion criteria:

• ECOG performance status (PS) 0-2 or Karnofsky PS 60-100%
• Life expectancy > 12 weeks
• Absolute neutrophil count ≥ 1.5 x 10^9/L
• Platelets ≥ 100 x 10^9/L
• AST ≤ 2.5 times upper limit of normal (ULN)
• Serum creatinine ≤ ULN
• Serum bilirubin ≤ 1.5 times ULN
• Negative pregnancy test
• Fertile patients must use effective contraception
• Able to understand and willing to sign a written informed consent document

Exclusion criteria:

• Allergies to or a history of allergic reactions attributed to any other compound of similar chemical or biologic composition to temsirolimus or metformin
• Diabetes mellitus (type I or II)
• Uncontrolled hypertriglyceridemia (triglyceride levels > 10 mmol/L)
• History of lactic acidosis
• Inability to swallow or digest oral medications

• Uncontrolled intercurrent illness including, but not limited to, any of the following:

  • Uncontrolled hypertension
  • Ongoing or active infection
  • Symptomatic congestive heart failure
  • Unstable angina pectoris
  • Cardiac arrhythmia
  • Psychiatric illness/social situation that would limit compliance with study requirements
• Significant traumatic injury within 21 days prior to treatment

PRIOR CONCURRENT THERAPY:

Inclusion criteria:

• Recovered from all prior therapy
• At least 4 weeks since prior chemotherapy or radiotherapy (6 weeks for carmustine or mitomycin C) except low-dose, non-myelosuppressive radiotherapy
• No limitation on other prior therapy
• Concurrent low-dose anticoagulant (i.e., warfarin) allowed provided INR ≤ 1.1 times ULN
• Concurrent full-dose anticoagulant (i.e., warfarin) allowed provided INR is within institutional therapeutic range (usually 2.0-3.0)

Exclusion criteria:

• Major surgery within the past 21 days
• Prior temsirolimus (or other known inhibitors of mammalian target of rapamycin) or metformin
• Concurrent combination antiretroviral therapy for HIV-positive patients
• Concurrent enzyme-inducing anti-epileptic drugs (EIAEDs) (e.g., phenytoin, carbamazepine, or phenobarbital) or other CYP3A4 inducer (e.g., rifampin or Hypericum perforatum [St. John's wort])
• Concurrent investigational or commercial agents or therapies to treat the patient's malignancy
• Other concurrent investigational agents other than temsirolimus or metformin