To date, more than twenty HDAC inhibitors have been initiated in clinical trials, and four HDAC inhibitors vorinostat (SAHA),13 romidepsin (FK-228),14 belinostat (PXD-101),15,16 panobinostat (LBH-589),17 have been approved by FDA for the treatment of T-cell lymphoma, cutaneous T-cell lymphoma and multiple myeloma. This evidence concerns the gene HDAC9 and AL amyloidosis.