Abstract:Multiple myeloma (MM) is a malignant tumor of the hematological system. Even if the patient reaches deep remission after treatment, it will eventually relapse, which may be related to clonal heterogeneity and clonal evolution. Clonal heterogeneity is a characteristic of MM. Under the pressure of bone marrow microenvironment and anti-tumor therapy, subclones follow different evolutionary patterns, such as branching evolution, linear evolution, neutral evolution and so on. Clonal evolution runs through all stages of MM, promoting the occurrence, drug resistance and relapse of MM. This article reviews the clonal heterogeneity, clonal evolution and clinical significance of MM, in order to provide new ideas for clinical treatment decision-making.