Comparison of calbindin D-28k and S-100 protein B in neuroblastoma as determined by enzyme immunoassay.

Levels of two calcium-building proteins, calbindin D-28k (calbindin-D) and S-100 protein B (S-100b), were measured by immunoassay in solid tumors obtained surgically from pediatric patients. Mean concentrations of calbindin-D and S-100b in 73 neuroblastomas (23 ganglioneuroblastomas and 50 neuroblastomas) were 10- or 25-fold higher, respectively, than those in other types of solid tumors in pediatric patients (n = 15). The mean tumor concentration of calbindin-D in patients with neuroblastoma (n = 73) was 25.1 ng/mg (range 0.20 to 317.0 ng/mg soluble protein, SE = 6.26); that of S-100b was 278.3 ng/mg (range 0.93 to 2521 ng/mg soluble protein, SE = 71.7). The mean concentration of calbindin-D (4.4 ng/mg soluble protein) was significantly (P < 0.05) lower in stage IV, the most advanced stage. The mean concentration of S-100b (74.0 ng/mg soluble protein) was lower in patients with undifferentiated neuroblastomas (P < 0.01). Tumor levels of the two calcium-binding proteins were not correlated in patients with neuroblastoma, but each was strongly correlated with outcome in patients with neuroblastoma. The evidence suggests that measurements of the calcium-binding proteins calbindin-D and S-100b would be useful for evaluating the prognosis of patients with neuroblastoma.