ENZYME-LINKED-IMMUNOSORBENT-ASSAY OF PRO-GASTRIN-RELEASING PEPTIDE FOR SMALL-CELL LUNG-CANCER PATIENTS IN COMPARISON WITH NEURON-SPECIFIC ENOLASE MEASUREMENT

Our previous study demonstrated that pro-gastrin-releasing peptide(31- 98), or ProGRP, is a specific tumor marker in patients with small cell lung carcinoma (SCLC). Using a newly developed, highly sensitive enzy me-linked immuuosorbent assay (ELISA) for ProGRP, we analyzed 1,446 sa mples including those obtained from 478 lung cancer patients to evalua te the clinical usefulness of this ELISA. Several properties indicated that ProGRP is a useful tumor marker for SCLC. First, ProGRP was spec ifically elevated in SCLC patients. In non-SCLC patients and patients with non-tumorous lung diseases, its serum level was very rarely eleva ted. Secondly, ProGRP was a reliable marker, in terms of the marked el evation of serum ProGRP levels in SCLC patients. Thirdly, serum ProGRP levels were elevated in SCLC patients even at a relatively early stag e of this disease. Fourthly, changes in the serum ProGRP level showed an excellent correlation with the therapeutic responses in SCLC patien ts, Neuron-specific enolase (NSE) is accepted as a tumor marker of SCL C patients, With the aim of comparing ProGRP and NSE as tumor markers for SCLC patients, we measured serum NSE levels in all samples collect ed in the present study, We found that ProGRP was superior to NSE in t erms of sensitivity, specificity and reliability, Therefore, we consid er that ProGRP can play a major role as a clinical tumor marker for SC LC patients.