[Mechanism of leukemia relapse: novel insights on old problem]

Relapse, which puzzled several generations of hematologists, is the bottle-neck of radical treatment for leukemias. The progress of Human Microbiome Project at the beginning of 21st century suggested that human body was a super-organism constituted by the core of human cells and symbiotic microorganisms. The elucidation and characterization of endogenous retrovirus and prion protein suggested the possible effects of co-evolutional microorganisms on human health. Recently, the elucidation of the roles of tunneling nanotubes in intercellular communication and transportation suggested a novel way for cellular communication and transport of oncogenic materials. The role and significance of in vivo cell fusion have been studied in more detail. On the other hand, donor cell leukemia was reported. All of these approaches provide novel insights for studying the mechanism of leukemia relapse. Based on previous work, the authors suggest the hypothesis: there are two possible mechanisms for the relapse of leukemias: the minimal residual disease (MRD) and intercellular transportation of oncogenic materials.