RESUMEN
<p><b>AIM</b>To explore the changes of epidermal growth factor (EGF) and epidermal growth factor receptor (EGFR) expressions in cryptorchid children and their clinical significance.</p><p><b>METHODS</b>The level of serum EGF was measured by radioimmunoassay (RIA) and the expression of EGFR by immunohistochemistry.</p><p><b>RESULTS</b>(1) The level of serum EGF was significantly lower in cryptorchid children than in normal subjects at age group of 5-9 years (P<0.01) and 10-14 years (P<0.01), (2) The level of EGF was significantly lower in boys with impalpable testis than in those with extracanalicular and intracanalicular testes (P<0.01), (3) The serum EGF level increased significantly 6 months after orchiopexy (P<0.05), (4) The EGFR expression in testicular Leydig's cells was lower in 2 approximately 4 year-old boys than in those over 5 years (P<0.05) and (5) the EGFR expression was less positive in the impalpable group and the intracanalicular group than that of the extracanalicular group (P<0.01).</p><p><b>CONCLUSION</b>The EGF and EGFR expressions may correlate with the age and the position of testes; orchiopexy improves the EGF and EGFR expressions in cryptorchid boys.</p>