Advances in Fusion Gene Research and Fusion Gene Families in Hematological Malignancies

Fusion genes (FGs) are major molecular biological abnormalities in hematological malignancies and have become well-established molecular markers for disease classification, risk stratification, and targeted therapies. The long tail phenomenon is observed in the distribution of FGs, which means that except for dozens of the most common FGs, the positive rates of the other FGs are all below 1%, even if they have been frequently reported in the literature. However, the total positive rate of these singly relatively rare FGs is actually not low due to their wide variety and numerous members. We therefore put forward the conception “fusion gene family, FG-FM” to describe fusions that share one common protagonist gene with different partner genes. Most of the FGs in hematological malignancies discovered to date can be classified into about 20 major families. Based on the characteristics of the currently reported FGs, it can be expected that although a great many FGs may be identified in the future, the total number of FG-FMs is rather limited. FGs in the same FG-FM often have similarities in pathogenicity, clinical features, and treatment outcomes. Classifying FGs according to FG-FMs will aid in understanding their pathogenicity and optimizing detection schemes.