A tumour suppresser gene, or anti-oncogene, is a gene that protects a cell from one step on the path to cancer. When this gene is mutated to cause a loss or reduction in its function, the cell can progress to cancer, usually in combination with other genetic changes. This book presents topical research data in the study of tumour suppressers, including Rab GTPases as potential tumour suppressers; the regulation of neutrophil function by tumour suppresser PTEN; the role of BRIT1/MCPH1 in genome maintenance and tumour suppression; epigenetic silencing of tumour suppressers; and the relationship between MicroRNA and tumour suppressers.