For example, miR-29b specifically targets HDAC4 to epigenetically regulate multiple myeloma cell growth and survival [1], miR-22 targets and inhibits HDAC4 in antigen-presenting cells and plays a critical role in emphysema and TH17 responses [7], miR-125a-5p targets HDAC4 to suppress breast tumorigenesis [3], and miR-140 and miR-365 target HDAC4 and participate in cartilage and bone development [20,21]. This evidence concerns the gene HDAC4 and AL amyloidosis.