Molecular Relapse in Acute Promyelocytic Leukemia. Case Report.

Abstract

Acute promyelocytic leukemia (APL) in childhood currently accounts between 15% and 20% of acute myeloid leukemia (AML) cases in our country. The mean age at diagnosis is 7-9 years. LPA has its own clinical and biological characteristics. The use of all-transretinoic acid (ATRA) combined with chemotherapy is the standard treatment with survival rates exceeding 80% in pediatrics. Patients included in the GATLA LPA-2007 protocol are regularly monitored for the PML/ RAR rearrangement. It´s very important to perform the quantitative measurement of this molecular rearrangement. Approximately 10-20% of children with APL treated with a therapy based on the use of ATRA and chemotherapy will experience an hematologic relapse, which can be detected early with molecular monitoring. Such a situation can be detected in the absence of haematological relapse. Minimal residual disease (MRD) monitoring by RQ-PCR allows identifying the presence of pathological cells when blast cells still represent a very low percentage, not detectable by standard microscopic examination. In this case, patients will be able to begin arsenic trioxide (ATO) therapy and will present fewer complications due to hyperleukocytosis and differentiation syndrome, compared with free frank hematological relapse. Studies of GIMEMA and PETHEMA groups have shown an advantage in the survival of those patients initiating salvage therapy when MRD (+) is detected early in surveillance. We report the case of a girl with molecular relapse of APL referring to the early detection by RQ-PCR.