Laboratory Test in Predicting Response to Erlotinib in Patients With Relapsed Metastatic or Unresectable Non-Small Cell Lung Cancer That Did Not Respond to Previous Treatment

DISEASE CHARACTERISTICS: * Histologically or cytologically confirmed metastatic or unresectable non-small cell lung cancer * Relapsed disease * Failed ≥ 1 prior chemotherapy regimen * Measurable disease * Tumor must be accessible to fine-needle aspiration * No uncontrolled brain metastases * Patients with brain metastases must have stable neurologic status after local therapy (surgery or radiotherapy) for ≥ 4 weeks and no neurologic dysfunction that would preclude evaluation of neurologic and other adverse events PATIENT CHARACTERISTICS: * ECOG performance status (PS) 0-2 OR Karnofsky PS 60-100% * Life expectancy \> 12 weeks * WBC \> 3,000/mm³ * Absolute neutrophil count \> 1,500/mm³ * Platelet count \> 100,000/mm³ * Bilirubin normal * PT and activated PTT normal * Creatinine normal OR creatinine clearance \> 60 mL/min * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * No uncontrolled intercurrent illness, including, but not limited to, any of the following: * Ongoing or active infection * Symptomatic congestive heart failure * Unstable angina pectoris * Cardiac arrhythmia * Psychiatric illness or social situation that would preclude study compliance * No significant ophthalmologic abnormalities\*, including any of the following: * Severe dry eye syndrome * Keratoconjunctivitis sicca * Sjögren's syndrome * Severe exposure keratopathy * Disorders that might increase the risk for epithelium-related complications (e.g., bullous keratopathy, aniridia, severe chemical burns, or neutrophilic keratitis) * No serious, nonhealing wound, ulcer, or bone fracture * No significant traumatic injury within the past 14 days NOTE: \*Patients with mild forms of any of the above ophthalmologic abnormalities, an asymptomatic history, or a normal ophthalmologic examination allowed at the discretion of the investigator. Patients with treatable conditions (e.g., infectious keratitis/conjunctivitis or allergic conjunctivitis) allowed after treatment or resolution of the condition. PRIOR CONCURRENT THERAPY: * See Disease Characteristics * No prior small molecule inhibitors of epidermal growth factor receptor, including erlotinib hydrochloride or gefitinib * At least 4 weeks since prior anticancer therapy, including chemotherapy, radiotherapy, biologic therapy, or other investigational therapy (6 weeks for nitrosoureas or mitomycin C) * More than 14 days since prior major surgery or open biopsy and recovered * At least 7 days since prior and no concurrent inhibitors of CYP3A4, including any of the following: * Itraconazole * Herbal extracts and tinctures, including any of the following: * Hydrastis canadensis (goldenseal) * Uncaria tomentosa (cat's claw) * Echinacea angustifolia roots * Trifolium pratense (wild cherry) * Chamomile * Licorice root * Dillapiol * Naringenin * No concurrent inducers of CYP3A4, including any of the following: * Phenytoin * Carbamazepine * Rifampin * Barbiturates * Hypericum perforatum (St. John's wort) * No concurrent chemotherapy * No other concurrent investigational agents * No concurrent combination antiretroviral therapy for HIV-positive patients * No concurrent radiotherapy, including palliative radiotherapy * No concurrent therapeutic anticoagulation * No other concurrent anticancer agents or therapies