ABSTRACT
BACKGROUND: Midkine (MK), a heparin-binding growth factor, is a secreted protein and can be detected in a patient's sera. METHOD: MK was studied in the sera of 215 children and adolescents without malignant disease using an enzyme-linked immunosorbent assay in order to determine the distribution of concentrations in a control population for pediatric oncology patients. Tested subjects either underwent surgical procedures or suffered from endocrinological diseases. RESULTS: Elevated MK levels were found in patients with short stature, diabetes mellitus, obesity, and cleft lip and palate. These patients were subsequently excluded from the "non-cancer" group. MK serum levels did neither correlate with sex, age, weight or height nor showed a normal distribution (n= 152, range: 0.0-5.58 ng/ml, median: 0.0 ng/ml, mean: 0.26 ng/ml, SD: +/-0.61). CONCLUSION: MK serum values in children and adolescents are widely spread and not normally distributed. The present results indicate that the MK expression is influenced by many factors apart from cancer, which have not yet been identified.
Subject(s)
Cytokines/blood , Adolescent , Age Factors , Child , Chronic Disease , Enzyme-Linked Immunosorbent Assay , Humans , Midkine , Neoplasms/blood , Reference ValuesABSTRACT
Serum levels of midkine (MK), a heparin-binding growth factor, are elevated in adult cancer patients. We analyzed sera of pediatric tumor patients in comparison to a large number of children and adolescents without malignant disease. MK was studied in sera of 152 noncancer patients and 29 embryonal tumor patients (14 nephroblastoma, 10 neuroblastoma, and 5 rhabdomyosarcoma) using an enzyme-linked immunosorbent assay. Noncancer patients underwent elective surgical procedures or suffered from an endocrinologic disease. They had no evidence of inflammation or injury. MK serum levels were significantly higher in tumor patients (median 0.621 ng/mL) than in noncancer patients. About 86% of tumor patients were identified using a cut-off value of 0.176 ng/mL. MK values did neither correlate with tumor size nor with stage or histology, but decreased in half of the nephroblastoma patients after chemotherapy and surgery. MK values were found to be elevated in only 2 out of 5 rhabdomyosarcoma patients. MK may serve as an additional marker for the detection of pediatric embryonal tumors, but its clinical relevance for the evaluation of response to therapy needs further study.
