Several studies showed that miRNAs act on various targets playing critical roles in the CLL pathogenesis, such as BCL2, C-FOS, C-MYC, TP53, TCL1, and STAT3. Both intracellular and exosomes miRNAs induce the B cells and B cell antigen receptor (BCR) activation, stimulate CLL cell progression, and could therefore be used as potential diagnostic and therapeutic biomarkers for CLL. The gene discussed is FOS; the disease is B-cell chronic lymphocytic leukemia.