Pro-gastrin-releasing peptide in patients with benign and malignant diseases.

The specificity and sensitivity of pro-gastrin-releasing peptide (ProGRP) was evaluated in 37 healthy subjects, 197 patients with benign diseases and 310 patients with malignant diseases of different origins. Abnormal ProGRP serum levels (>50 pg/ml) were found in 10% of the patients with benign diseases and in 26.1% of the patients with active cancer. None of the healthy subjects had abnormal ProGRP levels. The benign disease with the highest ProGRP concentration was renal failure, with abnormal values in 51.6% of the patients studied. Excluding patients with renal failure or patients with creatinine levels greater than 1.5 mg/dl, raised ProGRP values (<80 ng/ml) were found in 2.5% (4/160) of patients with benign diseases and in 4.9% of patients with active malignancies other than lung cancer or neuroendocrine tumors (<110 ng/ml). Abnormal ProGRP serum levels were found in 26.2% of patients with non-small cell lung cancer (NSCLC) (mean 40.5 +/- 35.4 pg/ml) and in 76.8% of patients with small cell lung cancer (SCLC) (mean 694 +/- 1,776 pg/ml) (p < 0.001). ProGRP serum levels >300 pg/ml were only found in SCLC patients (41.4%). ProGRP results were related to tumor extension in SCLC (sensitivity in limited disease 58.3%, in extensive disease 95.5%) but not in NSCLC. In summary, renal failure is the most frequent source of false-positive results with ProGRP, and this marker is useful in the histological differential diagnosis of lung cancer.