In addition, there is increased expression of several other proteins that promote cancer cell growth and proliferation, including those required to sustain proliferative signals, like B cell CLL/lymphoma 2 (Bcl-2), B-cell lymphoma-extra large (Bcl-xL), sirtuin 1 (SirT1), high-motility group AT-hook gene 1 (HMGA1) and other factors discussed below. Here, SIRT1 is linked to cancer.