Loss of heterozygosity of p16 correlates with minimal residual disease at the end of the induction therapy in non-high risk childhood B-cell precursor acute lymphoblastic leukemia.

We evaluated the incidence of MTS1/p16 deletions by loss of heterozygosity (LOH) analysis in 36 non-high risk B-cell precursor childhood acute lymphoblastic leukemia (BCP-ALL) and correlated these results with clinical features and with the presence of minimal residual disease (MRD) at the end of induction therapy. LOH was analyzed using three microsatellite markers flanking the p16 gene. MRD was studied by the polymerase chain reaction (PCR) for IgH and TCRdelta genes. All patients were classified and treated according to the BFM-86 protocol. A slower response to the induction treatment (MRD) was associated with LOH of p16 and worse clinical outcome. Thus, LOH of p16 may be a marker of chemotherapy resistance among the children classified as non-high risk BCP-ALL.