Spinophilin is a scaffolding protein with modular domains that govern its interaction with a large number of cellular proteins. The Spinophilin gene locus is localized at chromosome 17q21, a chromosomal region frequently affected by genomic instability in different human tumours. The scaffolding protein interacts with the tumour-suppressor ARF which has suggested a role for Spinophilin in cell growth. More recently, in vitro and in vivo studies demonstrated that Spinophilin is a new tumour suppressor acting via the regulation of pRb. A clear downregulation of Spinophilin is found in several human cancer types. Moreover, Spinophilin loss is associated with a poor patient prognosis in carcinoma. Currently, there are controversial findings regarding a functional relationship between Spinophilin and p53 in cell cycle regulation and in carcinogenesis. Here we present the available data regarding Spinophilin function as a tumour suppressor
