Hypermethylation of CpG island in the promoter region of CALCA in acute lymphoblastic leukemia with central nervous system (CNS) infiltration correlates with poorer prognosis

Promoter hypermethylation occurs early in leukemogenesis and seems to be associated with poor prognosis in acute lymphoblastic leukemia (ALL). The methylation status of the promoter region of six genes was analyzed in 71 children with ALL using methylation specific PCR (MSP). Calcitonin (CALCA) and E-cadherin (CDH1) were the most frequently methylated genes in this group of patients. Considering the patients with central nervous system (CNS) infiltration, the estimated 2-year overall survival (OS) was 20% for those with methylation in CALCA promoter and 85% for those without (p = 0.001). Our results suggest that the hypermethylation of CALCA promoter is a promising prognostic marker and may predict a higher risk for ALL patients with CNS infiltration.