RASSF1 and neoplasm: Identification of TSGs in the gene-rich 3p22–21.3 region has been challenging, although several candidate TSGs within this region showed tumour suppressor functions, such as RASSF1A (Pfeifer et al, 2002), SEMA3B (Tomizawa et al, 2001), BLU/ZMYND10 (Qiu et al, 2004), FUS1 (Zabarovsky et al, 2002) and HYA22 (RBSP3) (Kashuba et al, 2004), with some of them (RASSF1A and BLU) frequently inactivated by promoter methylation-mediated silencing.