Evaluation of a new tumor marker, CYFRA 21-1, in patients with primary lung cancer

We measured the level of serum CYFRA 21-1 (CYFRA) in 38 primary lung cancer patients (21 adenocarcinomas (ACs), 12 squamous cell carcinomas (SqCCs) and 5 small cell carcinomas (SmCCs)) before undergoing therapy using a 'CYFRA immunoradiometric assay kit'. We thus determined the CYFRA cut-off level to be 1.7 ng/ml. We also measured both the carcinoembryonic antigen (CEA), and the squamous cell carcinoma antigen (SCC) levels. The positive rate for CYFRA in patients with lung cancer was 71% and such positivity was related to their histology (SqCCs, SmCCs 100%; ACs 48%). The level of CYFRA was significantly higher in SqCCs than in either ACs or SmCCs. No significant differences were observed in the serum CYFRA value among the various clinical stages. In addition, no significant correlation was seen between CYFRA and SCC, or between CYFRA and CEA. Among the various clinical stages of SqCCs, the positive rate of CYFRA was higher in the early clinical stages than in SCC. Our findings therefore support the usefulness of CYFRA as a marker of SqCCs. (author)