Immune Escape of B-cell Lymphoblastic Leukemic Cells Through a Lineage Switch to Acute Myeloid Leukemia

Acute leukemia (AL) with a lineage switch (LS) is associated with poor prognosis. The predisposing factors of LS are unknown, apart from rearrangements that have been reported to be associated with LS. Herein, we present two cases and review all 104 published cases to identify risk factors for LS. Most of the patients (75.5%) experienced a switch from the lymphoid phenotype to the myeloid phenotype. Eighteen patients (17.0%) experienced a transformation from acute myelogenous leukemia (AML) to acute lymphoblastic leukemia (ALL). Forty-nine (46.2%) patients carried a rearrangement. Most of the cases involved LS from B-cell ALL (B-ALL) to AML (59.4%), and 49 patients (46.2%) carried -rearrangements. Forty patients (37.7%) received lineage-specific immunotherapy. Our findings suggest that the prevalence of rearrangements together with the lineage-specific immunotherapy may trigger LS, which supports the thesis of the existence of leukemia stem cells that are capable of lymphoid or myeloid differentiation.