Abstract: Objective:To investigate the expression of serum soluble B7-H4(sB7-H4)in patients with malignant lymphoma(ML),and its clinical significance.Methods:The serum levels of sB7-H4 in 71 cases with ML(including 59 primary patients and 12 recurrent patients) and 40 healthy people were detected by ELISA.The protein expressions of sB7-H4 in 30 cases of lymphoma tissue and 10 cases of lymphocyte hyperplasia tissue were detected by immunohistochemistry.Results:The serum levels of sB7-H4 in patients with non-Hodgkin lymphoma(NHL) and Hodgkin lymphoma(HL) were singnificantly higher than that in healthy control group(P<0.01).The serum level of B7-H4 in NHL group was higher than that in HL group(P<0.05).The serum level of sB7-H4 in primary group was significantly lower than that in recurrent group,and was significantly higher than that in healthy control group(P<0.01).The immunohistochemistry results showed that the positive rate of sB7-H4 in lymphoma tissue was higher than that in lymphocyte hyperplasia tissue(P<0.05).Conclusions:The serum expression of sB7-H4 in ML patients is high,which can provide a new tumor marker in the accessory diagnosis and prognosis of lymphoma.