Prognostic value of ERBB2 amplification and protein expression in small cell lung cancer

OBJECTIVE: Our objective was to evaluate ERBB2 oncogene amplification using fluorescence in situ hybridization (FISH) and protein overexpression using immumohistochemical techniques, and to explore their possible prognostic value in a series of patients with small cell carcinoma. PATIENTS AND METHODS: Included in the study were 99 patients with small cell tumors, classified in 2 broad groups: patients with limited locally advanced disease and patients with disseminated disease. Material for study was obtained in 97% of the cases (96/99) by means of endoscopic biopsy and by tomography-guided needle biopsy in the remaining 3% (3/99). Survival was analyzed using the Kaplan-Meier method. RESULTS: The 92 men (92.9%) and 7 women (7.1%) in the study had a mean (SD) age of 62.9 (10.4) years (range, 36-81 years); 39.4% (n=39) and 60.6% (n=60) of the subjects had limited and disseminated disease, respectively. ERBB2 protein overexpression was observed in 26.3% of the patients (n=26), 15.4% (n=4) of whom had limited disease and 84.6% (n=22) of whom had disseminated disease (P=.005). Although mean survival was slightly longer for patients who were negative for ERBB2 protein overexpression, the difference was not statistically significant. FISH identified gene amplification in 6.3% (1 in 16) of the studied cases (ratio, 2.3). CONCLUSIONS: The protein product of the ERBB2 oncogene is overexpressed in 33.3% of small cell lung carcinomas and is associated with the presence of disseminated disease. Further studies are necessary to evaluate the possible benefits of specific treatment.