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.