Evaluation of γ-enolase as a tumor marker for lung cancer

Abstract

The α‐enolase and γ‐enolase in tumor tissues and sera of patients with lung cancer were determined with an enzyme immunoassay system. Tissue γ‐enolase in small cell carcinoma of the lung (SCCL, n = 11), large cell carcinoma (n = 11), and non‐SCCL (except for large cell carcinoma) (n = 34) were enhanced approximately 35‐fold, ninefold, and fourfold, respectively; tissue γ/α + γ value of SCCL was significantly higher than that of normal lung tissue (P < 0.01). Serum γ‐enolase level was elevated (>6.0 ng/ml) in 14/18, 3/10, and 15/60 patients with SCCL, large cell carcinoma, and non‐SCCL (except for large cell carcinoma), respectively, and serum γ/α + γ value of SCCL was significantly higher than that of healthy subjects (P < 0.01). Immunohistochemically, the γ‐enolase was positive in 29/31 of the lung cancers. Serum γ‐enolase value is a useful tumor marker for staging and monitoring treatment of patients with lung cancer, and serum γ/α + γ value may be useful for differential diagnosis of SCCL from non‐SCCL or in differentiating lung cancers possessing neuroendocrine features from other lung cancers.