Clinical Study On WT1 Gene In Acute Leukemia Cells

Objective:â‘ To explore expression of Wilms' tumor gene (WT1) in acute leukemia (AL)cells and its clinical significance.â‘¡To study relation between WT1 gene and CD34expression in AL and its clinical significance.Methods:â‘ Real-time quantitative reverse transcription poiymerase chain reaction(RQ-RT-PCR) method was established for detecting WT1 expression levels in bonemarrow cells of 92 cases of de novo AL (M₀ 3 cases, M₁ 13 cases, M₂ 23 cases, M₃ 5cases, M₄ 6 cases, M₅ 12 cases, L₁ 18 cases, L₂ 8 cases, L₃ 4 cases ) and 35 cases ofnon-malignant blood disease. WT1 expression levels of WT1 of AL were detecteddynamically. The positive rates of WT1 expression were compared between AML and ALLgroups and between their sub-types. The expression levels of WT1 were comparedbetween different sub-types of AL. Primary complete remission (CR) rates and relapserates 6 months after remission were also compared between positive and negative groupsof WT1 expression.â‘¡Flow cell meter (FCM) was used to determine CD34 expression in92 cases of de novo AL before treatment. The relation between WT1 and CD34 expressionwas analied. Primary CR rates between groups CD34⁺ and CD34^-, WT1⁺CD34⁺,WT1⁺CD34^- and WT1^-CD34^- were compared.Results:â‘ Range of WT1 expression levels in 35 cases of control group is 0.5～147.6,median expression level is 15.8. AL cases whose WT1 expression levels＞200 aredefined as positive; Positive rate of WT1 expression of de novo AL patients is 67.4ï¼…(62/92); Positive rates of WT1 expression of AML and ALL are 72.6ï¼…(45/62) and56.7ï¼…(17/30) respectively. There is no significant difference (P＞0.05); Medianexpression levels of WT1 of AML and ALL are 692.6 and 678.8 respectively. There is no significant difference (P＞0.05); Positive rate of M₅ WT1 expression of de novo AMLsub-types is the highest(91.7ï¼…), significantly higher than that of M₀, M₁, M₂, M₃ and M₄;Median expression level of WT1 of M5 sub-type of AML is the highest (1308.6). There issignificant difference compared with sub-types of M₀, M₁, M₂, M₃ and M₄ (P＜0.05);Median expression level of WT1 of M₅ sub-type is significantly higher than that of allother sub-types of AL (P＜0.05); That means that WT1 expression level of monocyticleukemia is higher than that of granulocytic and lymphocytic leukemia; There is nosignificant difference of positive rate and median expression level of WT1 betweensub-types (L₁, L₂, L₃) of de novo ALL; CR rates of positive and negative groups of WT1expression of AL patients are 50.0ï¼…(31/62) and 90.0ï¼…(27/30) respectively. There isstatistic difference (P＜0.05); Relapse rate 6 months after remission of positive group ofWT1 expression (51.6ï¼…) is significantly higher than that of negative group (22.2ï¼…) (P＜0.05); Median expression of WT1 in bone marrow ceils of AL patients in de novo group,recurrence group and non-relieved group is significantly higher than that of CR group andcontrol group (P＜0.05); There is no statistic difference of bone marrow cells WT1expression between de novo, relapse and non-remission groups, CR and control groups (P＞0.05). With increase of WT1 expression level, CR rate decrease obviously; WT1expression level decreases significantly after CR and increases obviously after relapse.â‘¡Positive expression rate of CD34 of 92 cases of de novo AL patients is 44.6ï¼…(41/92 ); CRrates of positive and negative groups are 41.5ï¼…(17/41) and 80.4ï¼…(41/51) respectively;The difference has statistic significance (P＜0.001); Positive expression rate of WT1 of92 cases of de novo AL patients is 67.4ï¼…(62/92), positive expression rate of CD34 in 62cases of WT1⁺ patients is 62.9ï¼…(39/62), positive rate of WT1 expression of 41 cases ofCD34⁺ patients is as high as 95.1ï¼…(39/41), positive rate of WT1 expression of 51 casesof CD34^- patients is as low as 45.1ï¼…(23/51); Results of analysis the relation show thatWT1 is positively related to CD34 expression in AL (r_n=0.5304, x²=25.88, P＜0.005); 92 cases of AL patients are divided into 4 groups: WT1⁺CD34⁺, WT1⁺CD34^-, WT1^-CD34^- andWT1^-CD34⁺. After chemotherapy, primary relief rates are 33.3ï¼…(13/39), 73.9ï¼…(17/23),96.4ï¼…(27/28) and 50.0ï¼…(1/2) respectively. There are only 2 cases in WT1^-CD34⁺ group,which is excluded from statistics. Primary CR rates of remaining groups WT1⁺CD34⁺,WT1⁺CD34^- and WT1^-CD34^- were compared; There is significant statistic difference (P＜0.001). It means that CR rate is extremely low when WT1 and CD34 are positive,suggesting very poor prognosis; On the contrary, CR rate is very high when WT1 andCD34 are negative, suggesting relatively good prognosis.Conclusion:â‘ Expression of WT1 in bone marrow cells of AL patients can be a markerto evaluate occurrence, development and prognosis of the disease and to test minimalresidual disease (MRD).â‘¡Expression of WT1 in bone marrow cells of AL patients isrelated to that of CD34, positive expression of them is an important factor of low CR rate,poor therapeutic effect and prognosis.