Peptide hormone immunoreactivity and prognosis in small-cell carcinoma of the lung.

Paraffin-embedded specimens from a total of 94 small-cell carcinomas of the lung (SCCL) were screened for immunoreactivity to nine different peptide hormones (ACTH, calcitonin, gastrin, glucagon, growth hormone, human chorion gonadotropin, insulin, somatostatin and vasoactive intestinal peptide, VIP) using an indirect immunoperoxidase technique with commercially available kits. Special attention was focused on the prognostic significance of the peptide immunoreactivity. A total of 32 carcinomas (34%) showed immunoreactivity to one or more peptide hormones, the cases with ACTH reactivity (24.5%) far outnumbering those with reactivity to calcitonin (1.1%), somatostatin (1.1%), VIP (3.3%) or multiple peptides (4.3%). The mean survival of the patients was 8.4 months, being shorter (7.3 months) for the SCCLs with peptide reactivity than for the nonreactive carcinomas (9.2 months). The most favorable survival was found in VIP-reactive tumors (20.5 months), and the worst (2.0 months) in cases reactive to multiple peptides. The results suggest that immunohistochemical screening of the SCCL biopsies for the peptide hormones might be of benefit in predicting the clinical outcome of the disease.