Study of Blood and Tissue Samples in Predicting Response to Second-Line Therapy Using Erlotinib Hydrochloride or Chemotherapy in Patients With Advanced Non-Small Cell Lung Cancer

DISEASE CHARACTERISTICS:

* Histologically or cytologically confirmed diagnosis of non-small cell lung cancer (NSCLC)

  * Advanced NSCLC (stage IIIB or IV)
* Measurable disease
* Underwent previous treatment with 1 non-tyrosine kinase inhibitor as first-line therapy for advanced NSCLC
* No clinical evidence of uncontrolled brain metastases

PATIENT CHARACTERISTICS:

* Caucasian
* ECOG performance status 0-2
* Absolute granulocyte count ≥ 1,500/mm\^3
* Platelet count ≥ 100,000/mm\^3
* Bilirubin ≤ 1.5 times upper limit of normal (ULN) (≤ 2.5 times ULN in patients with known liver metastases)
* ALT or AST ≤ 3 times ULN (≤ 5 times ULN in patients with known liver metastases)
* Creatinine clearance ≥ 50 mL/min
* Not pregnant or nursing
* Able to comply with planned study procedures
* No multiple severe diseases that can compromise safety (cardiac and renal failure, peripheral neuropathy)
* No other malignancy (except for basal cell skin carcinoma) or pre-neoplastic condition requiring chemotherapeutic treatment

PRIOR CONCURRENT THERAPY:

* See Disease Characteristics
* At least 3 weeks since prior surgery or radiotherapy