OBJECTIVE: To explore the relationship between human cyclin C (CCNC) gene and childhood acute lymphocytic leukemia (ALL). MethodsThe total RNA isolated from myeloid tissues of normal children and of children with newly diagnosed ALL and from ALL cell line 6T-CEM was reversely transcribed into cDNA. Real-time fluorescence quantitative PCR method was used to detect CCNC gene expression. RESULTS: CCNC was expressed in myeloid tissues of normal children and of children with newly diagnosed ALL as well as 6T-CEM. The relative expression level of CCNC gene in children with newly diagnosed ALL was significantly lower than in normal controls (2.35±0.83 vs 13.5±0.30; P<0.05). CONCLUSIONS: CCNC gene shows lower expression in children with newly diagnosed ALL, suggesting that it may be a tumor suppressing gene in childhood ALL.