LEUCEMIA MIELÓIDE CRÓNICA: DESAFIOS NO TRATAMENTO DA FASE BLÁSTICA. A propósito de um caso clínico

Chronic Myeloid Leukemia is characterized by the reciprocal translocation between chromosomes 9 and 22 – Philadelphia chromosome. Without treatment this neoplasia would evolve with relative rapidity from chronic to accelerated phase, culminating in a blast crisis. Although tirosin kinase inhibitors were a major discovery that led to advances in treatment, there are still reported cases of resistance to treatment and evolution to blast crisis, a disease phase of difficult management and poor prognosis. On this assay, we report a patient resistant to the three tirosin kinase inhibitors nowadays approved, which develops a complex karyotype and an E255K mutation. In this particular case, this mutation appears not to be of clinical significance. Thus, the clinical relevance of this kind of mutation is found to be questionable. The case here reported corroborates the inability of tirosin kinase inhibitors in killing all leukemic cells hypothesis, and the theoretical presence of other pathways beyond the described tirosin kinase pathway. Simultaneously, is presented a review of recent mechanisms of resistance, new prognostic biomarkers still under investigation and new developments in therapy.