COPS5 and lung cancer: Curcumin (a CSN5 inhibitor) inhibits HCC and lung cancer progression via deubiquitination on HK2 [238]; AC17, a 4-arylidene curcumin analog, inhibits 19S while not affecting 20S deubiquitinase activity, causing a noticeable accumulation of polyubiquitinated proteins in lung cancers, and it improves cancer progression and metabolism [239].