The alpha subunit of GTP-binding protein G0 in neuroblastoma: correlation with advanced disease stage

Tissue levels of the alpha subunit of G protein G0 (G0 alpha) were measured in solid tumors from pediatric patients by immunoassay. G0 alpha concentrations were determined in the supernatant obtained by centrifugation of tissue homogenates prepared in the presence (total G0 alpha) or absence of 2% sodium cholate (soluble G0 alpha). Mean G0 alpha concentrations (total G0 alpha and soluble G0 alpha) in neuroblastomas (7 ganglioneuromas, 13 ganglioneuroblastomas, and 50 neuroblastomas) were over 50-fold higher than those in other solid tumors from pediatric patients (n = 13). Mean total G0 alpha and soluble G0 alpha concentrations were 207.0 +/- 166.0 (SD) ng/mg of cholate-extractable protein and 58.6 +/- 47.0 ng/mg of soluble protein, respectively, in the neuroblastoma group (n = 70). Total G0 alpha concentration decreased with disease stage and was strongly correlated with outcome in patients with neuroblastoma. The mean total G0 alpha concentration in tumors from younger patients (< 1 year old) was 297.0 +/- 137.0 ng/mg of cholate-extractable protein, significantly higher than in tumors from older patients (140.0 +/- 155.0 ng/mg cholate-extractable protein, P < 0.0001). These results suggest that total G0 alpha levels in neuroblastoma may indicate the degree of malignancy.