Large cell carcinoma of the lung. Prognostic implications of histopathologic and immunohistochemical subtyping

Fifty-four patients with large cell carcinoma of the lung were treated surgically, and the prognostic factors were examined histologically and immunohistochemically. Based on evidence of intercellular cohesion, as seen in the histologic results, the patients were placed into two subtypes, compact growth type and louse structure type. The survival rates were 46% and 28% at five years, respectively (P less than 0.05). Immunohistochemically, keratin, epithelial membrane antigen (EMA), secretory component, lactoferrin, and carcinoembryonic antigen (CEA), as histologic markers of epithelial differentiation, were detectable in large cell carcinoma of both types and more frequently in the compact growth type than in the loose structure type. The difference was significant in case of detection of keratin, EMA, and CEA (P less than 0.05). These observations suggest that a large cell carcinoma may differentiate into an adenocarcinoma or squamous cell carcinoma. The presence of intercellular cohesion and use of these markers reflect prognosis of the disease.