Concentration of zinc and zinc-copper superoxide dismutase activity in red blood cells in normals and children with cancer

Zinc concentrations and Cu, Zn superoxide dismutase activity in erythrocytes were investigated in 138 healthy children and in 35 children with cancer. The mean zinc concentration in the erythrocytes of healthy children was found to be age-dependent. In the youngest group (children up to 1 year of age) the zinc concentration in erythrocytes is 18.8 +/- 3.4 micrograms/g Hb (5.89 +/- 1.23 mg/l packed cells), which is significantly lower than in other age groups. A strong logarithmic correlation (r = 0.327, p less than 0.0001 and r = 0.436, p less than 0.00001) was found between age and zinc concentration in erythrocytes, expressed as microgram/g Hb and as mg/l packed red cells, respectively. Cancer children were divided into two groups (neuro- and nephroblastoma). In the group of children with neuroblastoma no statistical differences in zinc concentration or enzyme activity were observed. In the patients with nephroblastoma, significantly higher zinc concentrations (p less than 0.05) were observed in erythrocytes. The changes of zinc concentration are accompanied by significant (p less than 0.02) decreases of enzyme activity. In this group of cancer children, statistically significant differences were observed in the zinc concentrations in erythrocytes (microgram/g Hb) between the second and the third stages of the disease. No correlation was observed between the concentration of zinc and enzyme activity in healthy children or in cancer children.