DISEASE CHARACTERISTICS:

• Histologically confirmed endometrial carcinoma

  • Recurrent or persistent disease
  • Histologic confirmation of the original primary tumor is required
• Refractory to curative therapy or standard treatments

• Measurable disease

  • At least 1 unidimensionally measurable lesion ≥ 20 mm by conventional techniques, including palpation, plain x-ray, CT scan, or MRI OR ≥ 10 mm by spiral CT scan

  • Must have at least 1 target lesion

    • Tumors within a previously irradiated field are considered non-target lesions

      • Disease in an irradiated field as the only site of measurable disease is considered a target lesion provided there has been clear progression of the lesion since the completion of prior radiotherapy

• Must have received 1 prior chemotherapy regimen for endometrial carcinoma

  • Initial therapy may have included high-dose therapy, consolidation, or extended therapy administered after surgical or non-surgical assessment
  • No more than 1 additional prior cytotoxic regimen for recurrent or persistent disease
• Tumor accessible to guided core needle or fine needle biopsy
• Ineligible for a higher priority GOG protocol (e.g., any active GOG phase III protocol for the same patient population)

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• GOG 0-2 (for patients who have received 1 prior treatment regimen)
• GOG 0-1 (for patients who have received 2 prior treatment regimens)

Life expectancy

• Not specified

Hematopoietic

• Absolute neutrophil count ≥ 1,500/mm^3
• Platelet count ≥ 100,000/mm^3

Hepatic

• Bilirubin ≤ 1.5 times upper limit of normal (ULN)
• SGOT ≤ 2.5 times ULN
• Alkaline phosphatase ≤ 2.5 times ULN

Renal

• Creatinine ≤ 1.5 times ULN

Cardiovascular

• Cardiac ejection fraction normal by echocardiogram or MUGA

Gastrointestinal

• No gastrointestinal (GI) tract disease resulting in an inability to take oral medication
• No malabsorption syndrome
• No requirement for IV alimentation
• No uncontrolled inflammatory GI disease (e.g., Crohn's or ulcerative colitis)

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• No active infection requiring antibiotics
• No sensory or motor neuropathy > grade 1
• No history of allergic reaction attributed to compounds of similar chemical or biological composition to lapatinib
• No other invasive malignancy within the past 5 years except nonmelanoma skin cancer

PRIOR CONCURRENT THERAPY:

Biologic therapy

• At least 4 weeks since prior immunologic agents for the malignant tumor
• No prior trastuzumab (Herceptin^®) or any target-specific therapy directed to the HER family (e.g., gefitinib, erlotinib, or cetuximab)

Chemotherapy

• See Disease Characteristics
• At least 6 weeks since prior nitrosoureas or mitomycin for the malignant tumor and recovered
• No prior non-cytotoxic chemotherapy for recurrent or persistent disease

Endocrine therapy

• At least 1 week since prior hormonal therapy for the malignant tumor
• Concurrent hormone replacement therapy allowed

Radiotherapy

• See Disease Characteristics
• Recovered from prior radiotherapy

Surgery

• Recovered from prior surgery
• No prior surgery affecting absorption

Other

• At least 4 weeks since other prior therapy for the malignant tumor
• No prior lapatinib
• No prior anticancer treatment that would preclude study treatment
• Concurrent oral anticoagulants (e.g., warfarin) allowed provided there is increased monitoring of INR
• No concurrent CYP3A4 inducers or inhibitors
• No concurrent combination antiretroviral therapy for HIV-positive patients