Correlation of Altered Expression of RIZ1 to Diagnosis, Risk Stratification, and Disease Progression in 56 Acute Leukemia Patients.

Abstract 2627

Poster Board II-603

RIZ1 expression is altered in a variety of human cancers and is now considered to be a candidate tumor suppressor in many types of human tumors, including breast cancer, liver cancer, colon cancer, neuroblastoma, melanoma, lung cancer, and osteosarcoma. Previous studies indicate that suppression of RIZ1 expression may have an important role in leukemogenesis and RIZ1 is downregulated during CML progression and displays tumor suppressor properties in CML cell lines. To deeply investigate the expression of RIZ1 and its correlation to diagnosis, risk stratification, and disease progression in human acute leukemia, we analysed the differential expression of RIZ1 by quantitative real-time reverse-transcription polymerase chain reaction assay in 56 acute patients with or without complete remission and in 9 healthy donors. Our results showed that the expression of RIZ1 was significantly decreased in both de novo acute leukemia patients and patients with no remission (n = 35) (P = 0.009, compared with healthy donors) and significantly increased in acute leukemia patients with complete remission (P = 0.001, compared with de novo acute leukemia patients and patients with no remission). When compared with healthy donors, acute leukemia patients with complete remission (n = 21) owned the statistically same expression of RIZ1 (P = 0.595). The expression of RIZ1 was significantly higher in acute myeloid leukemia (AML, n = 17) than acute lymphoblastic leukemia (ALL, n =15) (P = 0.009), with a good correlation to diagnosis of AML or ALL (r = 0.514). The patients (n = 16) with high-risk leukemia had significantly higher expression of RIZ1 than the patients with standard-risk (n = 18) (P = 0.031), with the correlation (r = 0.431) of RIZ1 expression to disease risk-stratification. In addition, the weak correlations of RIZ1 expression were shown to both age and gender ( r = 0.158 and 0.003, respectively). This relatively simple analysis provides an important role of RIZ1 expression in acute leukemia. Taken together, our results suggest the potential for using RIZ1 expression in predication of disease progression or recovery in acute leukemia. We demonstrate that RIZ1 expression can contribute to the diagnosis of AML or ALL and the evaluation of risk-stratification in acute leukemia.