ABSTRACT
<p><b>OBJECTIVE</b>To investigate the relationship of Ki-67 level with clinical features, immunophenotype, gene mutation, curative efficacy and prognosis in patients with acute lymphoblastic leukemia(ALL).</p><p><b>METHODS</b>Flow cytometry gated at CD45/SSC was used to detect the expression of Ki-67, and the correlation of Ki-67 expression with clinical manifestation, laboratorial indexes, curative efficacy and prognosis was analysed.</p><p><b>RESULTS</b>Ki-67 expression level increased in ALL patients, the median expression rate was 29.22%, there was significant difference as compared with the healthy control (P<0.01). In adult ALL, the median expression rate of Ki-67 in the high-risk group was 31.49%, and the difference was statistically significant as compared with the low-risk group (P<0.05). In children ALL, the median expression rate of Ki-67 in high-risk group was 42.28%, and the difference was statistically significant (P<0.05). The results of unvariate analysis showed that the age, WBC count at newly diagnosed and extramedullary invasion were adverse factors affecting OS and DFS; the results of multivariate analysis showed that age and extramedullary invasion were independent risk factors for OS and DFS in patients.</p><p><b>CONCLUSION</b>Age≥14 years old, intramedullary invasion are the poor factors for prognosis; the Ki-67 level is not an independent factor for the prognosis of patients.</p>