Clinicopathologic characteristics of patients with nonsmall cell lung carcinoma with elevated serum progastrin-releasing peptide levels.

BACKGROUND

Progastrin-releasing peptide (proGRP) is a specific tumor marker in patients with small cell lung carcinoma (SCLC). It has been reported that serum proGRP levels rarely are elevated in patients with nonsmall cell lung carcinoma (NSCLC); the reported frequency is <3%. The purpose of this study was to examine the clinicopathologic features of NSCLC patients with high serum proGRP levels.

METHODS

The authors measured serum proGRP levels with a TND-4 kit, a newly developed enzyme-linked immunoadsorbent assay, in 544 NSCLC and 206 SCLC patients. Pathologic features were examined using conventional hematoxylin and eosin staining and histochemical and immunohistochemical staining using polyclonal antibodies to proGRP, chromogranin A, calcitonin, and monoclonal antibody to the neural cell adhesion molecule (NCC-Lu-243).

RESULTS

The serum proGRP levels were elevated in 140 SCLC patients (68.0%) and in 23 NSCLC patients (4.2%). Seven of these 23 NSCLC patients had serum proGRP levels > or = 100 pg/mL. They included two patients with renal dysfunction, one patient diagnosed cytologically with adenocarcinoma without undergoing precise pathologic examination, two patients diagnosed histologically with squamous cell carcinoma with foci of small cell elements, and two patients diagnosed with large cell neuroendocrine carcinoma and poorly differentiated adenocarcinoma, respectively, which showed neuroendocrine differentiation on immunohistologic analysis. The remaining 16 NSCLC patients had serum proGRP levels < 70 pg/mL.

CONCLUSIONS

Nearly all NSCLC patients had serum proGRP levels < 100 pg/mL. However, if an NSCLC patient presents with a proGRP level > or = 100 pg/mL, the clinicopathologic features must be examined with regard to the small cell component, neuroendocrine differentiation, and renal dysfunction.