Immunohistochemical expression of p53, bcl-2 and p21waf1 in an Argentinean pediatric Non Hodgkin’s lymphoma series.

PAOLA ANDREA CHABAY; DE MATTEO, E; PRECIADO, M. V.

APPLIED IMMUNOHISTOCHEMISTRY

Lippincott Williams & Wilkins

Año: 2006 vol. 14 p. 12 - 17

1062-3345

Lymphoma accounts for 10% of all childhood cancers in developed countries.  In Argentina, the incidence is 13.6%.  Of these 53% are non Hodgkin lymphomas (NHL) and 47 % are Hodgkin’s lymphomas (HL). Overexpression of p53, p21waf1 and bcl-2 has been studied mainly in adult NHL and less of them in the pediatric population, and then correlated with clinical features and survival. Our aim was to analyze overexpression of these cellular oncogenes in pediatric NHL. Methods: Formalin-fixed paraffin-embedded lymph node biopsies from 48 pediatric patients with NHL were studied by immunohistochemistry with monoclonal Abs for p53, bcl-2 and p21waf-1. Results: Overexpression of p53 was detected in 81% of cases, bcl-2 positivity was 46% and p21waf1   positivity was 42%.  The p53/p21waf1 expression patterns (types IV and V patterns), which correspond to the overexpression of non functional p53, accounted for 46% of NHL. No of the studied oncogene pattern correlated with poor clinical patient outcome or histological subtype.  Conclusions:  Of 81% of cases with p53 overexpression, 46% exhibited a non functional p53 pattern, and may contribute to dysregulation of proliferation.  Bcl-2 expression in up to 46% of cases, may reflect a failure of bcl-2 downregulation in pre-B and immature B cells.