Squamous cell carcinoma antigen in lung cancer and nonmalignant respiratory diseases

Study Objectives Squamous cell carcinoma antigen (SCC) has been found in elevated amounts in patients with squamous cell lung cancer (SQLC). Elevated levels have also been found among patients with nonsquamous cell lung cancer (NSQLC) and in subjects with nonmalignant pulmonary disease (NMPD). The purpose of the current study was to evaluate SCC levels among a large number of patients with SQLC, NSQLC, and NMPD. Six hundred thirty-nine lung cancer patients, including 201 SQLC patients and 299 patients with NMPD, who were diagnosed at our hospital up to 2006 were entered. Serum SCC levels were measured with a commercially available kit. Results Elevated levels (> 1.5 ng/ml) of SCC were observed in 52.7% of SQLC patients, but in only 14.2% of NSQLC patients. There was a statistically significant difference in positive rate between SQLC and NSQLC patients. None of the NSQLC patients had serum SCC levels greater than 40.0 ng/ml. Among subjects with NMPD, 28.4% had elevated levels of SCC. However, none of the NMPD patients had serum SCC levels greater than 20.0 ng/ml. Conclusions Serum levels of SCC can be elevated (< 20.0 ng/ml) in some NMPD patients without coexisting SQLC. Patients with NSQLC and NMPD with elevated SCC levels greater than 40 ng/ml may have coexisting SQLC or squamous cell carcinoma in an extrapulmonary site.