Small Non-Coding RNAs in Leukemia

Simple Summary Leukemia is a group of blood cancers that arise when abnormal or underdeveloped blood cells accumulate in the bloodstream, bone marrow and lymphatic system. A driver event in the development of Chronic Lymphocytic Leukemia (CLL) is the deletion of the genomic region encoding for miR-15a/16-1. MicroRNAs are small non-coding RNAs involved in the regulation of gene expression, and loss of miR-15a/16-1 in CLL results in the accumulation of the antiapoptotic gene BCL2 and inhibition of the apoptotic process. This discovery was the first evidence that microRNAs have a role in the onset of cancer. Following this finding, several studies investigated the role of microRNAs and other small non-coding RNAs in different types of leukemia and cancers in general. This review summarizes the role of small non-coding RNAs in leukemia and describes their possible application in clinical settings as biomarkers and/or targets for therapy. In 2020, more than 60,500 people were diagnosed with leukemia in the USA, and more than 23,000 died. The incidence of leukemia is still rising, and drug resistance development is a serious concern for patients' wellbeing and survival. In the past two decades, small non-coding RNAs have been studied to evaluate their functions and possible role in cancer pathogenesis. Small non-coding RNAs are short RNA molecules involved in several cellular processes by regulating the expression of genes. An increasing body of evidence collected by many independent studies shows that the expression of these molecules is tissue specific, and that their dysregulation alters the expression of genes involved in tumor development, progression and drug response. Indeed, small non-coding RNAs play a pivotal role in the onset, staging, relapse and drug response of hematological malignancies and cancers in general. These findings strongly suggest that small non-coding RNAs could function as biomarkers and possible targets for therapy. Thus, in this review, we summarize the regulatory mechanisms of small non-coding RNA expression in different types of leukemia and assess their potential clinical implications.