RATIONALE: Collecting and storing samples of tissue from patients with cancer to study in the laboratory may help doctors learn more about changes that may occur in DNA and identify biomarkers related to cancer.

PURPOSE: This laboratory study is looking at epidermal growth factor receptor mutations and k-ras oncogene mutations in patients with stage III non-small cell lung cancer.

OBJECTIVES:

• Determine the frequency of epidermal growth factor receptor (EGFR) and K-ras mutations in patients with stage III non-small cell lung cancer (NSCLC) treated on CALGB 30106.
• Correlate presence or absence of EGFR and/or K-ras mutations with radiographic response to treatment in these patients.

OUTLINE: Tissue samples are analyzed for epidermal growth factor receptor and K-ras mutations.

Inclusion criteria:

1. Eligible patients had histologic documentation of un- treated stage III NSCLC.
2. Radiation oncologist confirmation was required that radiation could be given per protocol.
3. Eastern Cooperative Group Criteria Performance Status of 0 to 2
4. Tumor specimen paraffin block or unstained slides and standard initial laboratory tests
5. Signed institutional review board-approved, protocol-specific in- formed consent in accordance with federal and institutional guidelines

Exclusion criteria:

1. Patients with scalene, supraclavicular, or contralateral hilar lymph node involvement, or direct invasion of the vertebral body or with a pleural effusion were ineligible.

Patients diagnosed with stage III non-small cell lung cancer.