Abstract: Abstract:Objective To investigate the factors affect on the clinicopathological characters, the outcome treatment and the prognostic of anaplastic large cell lymphoma (ALCL). Methods The clinical data of 45 patients with ALCL who received treatment in our hospital from Jan 2000 to Dec 2008 were analyzed retrospectively. The survival was estimated by Kaplan-Meier and the prognostic factors were analyzed with Cox model. Results 84.4% (38 patients) and 15.6% (7 patients) were primary cutaneous and systemic ALCL respectively. Twenty patients (44.4%) manifested with systemic symptoms and 8 patients （21.6%）with elevated level of lactate dehydrogenase. According to the International Prognostic Index (IPI) of Non-Hodgkin lymphoma, 31 patients（68.9%）were the low and low-intermediate risk. And anaplstic lymphoma kinase (ALK) was positive in 28 patients (62.2%). 26 patients (57.8%) were T-cell origin, 6 ones (13.3%) were B-cell origin markers 11 ones（22.2%）were null type and both the T-cell and B-cell markers were positive in the other two patients (4.4%). The response rates, 5-year overall survival rates of primary cutaneous and systemic ALCL were 100% and 92.1%, 83.3% and 63.9% (χ2=0.707，P＝0.401) respectively. The 5-year overall survival rates of patients with positive and negative ALK were 87.5% and 46.9% (χ²=10.992，P＝0.01). With the univariate analysis，the expression of ALK(P＝0.01), the score of IPI (P＝0.000) and the clinical staging (P＝0.005) were the prognostic factors affect the overall survival. With multivariate analysis, both ALK (0.012) and IPI (P＝0.000) were the independent prognostic factors. Conclusion Approximately, 80% of ALCL are primary systemic and 60% of patients express the ALK. Both the response and the survival are satisfied. The ALK and IPI score are the independent prognostic factors affect the overall survival.