Peripheral airway cell marker expression in non-small cell lung carcinoma. Association with distinct clinicopathologic features.

Paraffin sections of 247 primary and metastatic non-small cell lung carcinomas, the corresponding non-neoplastic lungs, and 75 other specimens were examined by immunohistochemical procedures using a panel of antibodies against the specific products of peripheral airway cells: the major surfactant-associated protein and 10-kD Clara cell protein. Non-small cell lung carcinoma tumors most frequently positive for either peripheral airway cell marker were adenocarcinomas (41%), especially those with papillolepidic growth pattern (56%), followed by large cell carcinomas (25%), other adenocarcinomas (22%), and squamous cell carcinomas (16%). Immunoreactivity was mainly focal and the expression of the two peripheral airway cell markers was discordant. The incidence of marker expression was similar in metastatic and primary non-small cell lung carcinoma. Other organs and their tumors were negative, with few exceptions. Non-small cell lung carcinomas positive for peripheral airway cell markers were associated with younger age and less-intense smoking, and surfactant-associated protein reactivity was more common in women than in men. Peripheral airway cell markers were independent prognostic factors for survival and delayed development of metastases in patients with less-advanced disease. It is concluded that surfactant-associated protein and 10-kD Clara cell protein are specific markers for non-small cell lung carcinoma and peripheral airway cell differentiation and provide useful tools to study the pathogenesis, biology, and prognosis of non-small cell lung carcinoma.