Abstract:The retinoblastoma-protein-interacting zinc finger protein1 (RIZ1), a methyltransferase, contains the characteristic PR zinc finger domain. RIZ1 can methylate H3K9 of the histone, acted as a transcription suppression factor of cancers. Increasing numbers of human cancers are reported to hold decreased or absent RIZ1 expression, which is closely related to the progression of cancer. RIZ1 is defined as a candidate anti-oncogene. The mechanisms of the suppression involved in both oncocytogenetics and epigenetic changes.