HK1 and cancer: The lack of an shHK2 inhibitory response for HK1+HK2+ cancer cells is not unique to liver cancer cells; shHK2 inhibition of HK2 expression is unable to prevent proliferation or colony formation in HK1+HK2+ tumor cell lines derived from lung, breast, or colon cancers (Fig. 2c, d) as well as HK1+HK2+ liver cancer cells.