Melo, A.; Artigas, C. G.; Fritz, C.; Díaz, P.; Muñoz, S.; Brebi, P. & Roa, J. C.

Summary

Acute lymphoblastic leukemia (ALL) is the most common hematology oncology malignancy in pediatric patients counting up to 75% of leukemias and 32­35% of all childhood cancers. Although ALL is considered a disease with a genetic basis, it is increasingly clear that epigenetic alterations play a central role in the pathogenesis and work was to determine the methylation status in promoter-exon1 of the TSG-p53 and association with survival in children under 15 years with ALL. In our study 40 patients from the Araucanía Region, Chile were analyzed. Hypermethylation of p53 was determined by combining restriction enzymes sensitive to methylation (HpaII and EcoR II) and polymerase chain reaction. Results indicated that 15/40 cases (37.5%) showed hypermethylation. Statistical difference was found in survival according to p53 methylation status in the girls group (p=0.02). Considering all patients, there was a trend to improved survival when leukocyte counts were <30.000/ul (p=0.08). We found the p53 gene frequently hypermethylated in the promoter-exon1 region. This would indicate that TSG p53 hypermethylation may be an important event in the pathogenesis of ALL.

KEY WORDS: Hypermethylation; p53 tumor suppressor gene; Acute lymphoblastic leukemia; Childhood leukemia, Survival.

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