CCND1 and carcinoma: In addition, cyclin D1, a key protein involved in the regulation of cell proliferation and differentiation [43] and often augmented in human carcinomas, was upregulated with FAC treatment in RT-PCR, immunostaining, and Western blot, and this iron-induced cyclin D1 expression was prevented in FAC samples treated with GLUT3si (Figure 4C–E).