p53 expression in biopsies from children with Langerhans cell histiocytosis

Purpose: Langerhans cell histiocytosis (LCH) is a rare pediatric and adult disease causing skin rashes, osteolytic bone lesions, tumorous growth in various organs, and in some patients, organ dysfunction. The cause of the disease is obscure, and it is not yet understood why some patients develop single-system lesions only without relapse, whereas others develop fatal multiorgan disease. The expression of p53 tumor suppressor gene product detected immunohistochemically can be used as a guideline to alterations in DNA repair control and apoptosis. The authors have chosen to analyze p53 expression in biopsies from children with LCH and correlate it with clinical manifestation and outcome in a broad range of organs. Patients and Methods: The study was performed on 50 specimens from 32 children (19 boys and 13 girls), median age 3 1/4 years, range 5 months to 12 1/3 years with a definite diagnosis of LCH based on CD1a positivity. The slides were stained with p53 antibody and semiquantitatively evaluated using a grading system from 1 to 5 as an estimate for 0% to 20%, 20% to 40%, 40% to 60%, 60% to 80%, and 80% to 100% p53-positive for pathologic Langerhans cells (pLC), respectively. Results: The p53 protein was expressed in various degrees in pLC in all lesions. The degree of p53 expression could not be correlated to either clinical manifestation or outcome. Conclusions: An increased expression of p53 in pLC indicates an altered DNA repair control with or without abnormal control of apoptosis.