[NT5C2 expression in children with acute leukemia and its clinical significance]

To investigate the expression level and analyze the clinical significance of NT5C2, which is an nucleoside analogues metabolism related gene, in children with acute leukemia (AL).

Real-time PCR and immunohistochemistry were presented to detect the level of NT5C2 mRNA and its protein product cN- Ⅱ in bone marrow samples of 63 patients initially diagnosed with AL, 15 patients who achieved complete remission, 7 patients who relapsed and 16 non- hematologic malignancie controls. The expression of NT5C2 mRNA in different groups of AL and its relevance with clinical indicators were analyzed.

①The expression of NT5C2 mRNA in newly diagnosed B-ALL, TALL, AML and controls were 1.16 (0.89-2.25, 0.96 (0.74-1.25, 1.66 (0.84-3.15) and 0.88 (0.61-1.21), respectively. NT5C2 mRNA expression in AML (P<0.01) and B-ALL (P<0.05) cases were higher than that in controls; NT5C2 mRNA expression in T- ALL and in controls showed no significant difference (P>0.05). Changes of NT5C2 mRNA level were observed between preliminary diagnosis and complete remission in 15 patients. NT5C2 mRNA levels were significantly decreased in complete remission stage than that in newly diagnosis AL (P<0.01). NT5C2 mRNA levels of relapsed-refractory group were higher than that of complete remission group and controls (P<0.01). ② Immunohistochemical staining results revealed that NT5C2 protein levels were consistent with the trend of mRNA levels. ③NT5C2 mRNA levels in AML (r=0.434) and T-ALL (r=0.389) were positively correlated with risk classification (P<0.05). ④ During chemotherapy of patients with AML, the NR rate of bone marrow in NT5C2 high expression group was higher than that of low expression group after 9 days induction chemotherapy (35.2% vs 0) and before consolidation therapy (25.0% vs 0); The positive rate of minimal-residual disease (36.4% vs 14.3%) and relapse rate of AL (38.5% vs 28.6%) were increased in NT5C2 high expressed patients than that in low expressed patients, but all the differences were insignificant (P>0.05).

High expression of NT5C2 was found to be a related risk factor of AL children with unfavourable prognosis. NT5C2 promises a new target for guiding individualized chemotherapy and evaluating the prognosis of childhood acute leukemia and monitoring recurrence.