GRP and small cell carcinoma: Serum levels of neuron-specific enolase (NSE) and pro-gastrin-releasing peptide (pro-GRP), tumor markers of small-cell carcinoma, were also elevated [NSE, 25.8 ng/ml, (normal range, 0–12 ng/ml); pro-GRP, 152.0 pg/ml (normal range, <80.0 pg/ml)].