This study is to evaluate the clinical value of serum tumor supplied group of factors(TSGF) in diagnosis of canine cancer.145 dogs with malignant tumors,32 benign diseases,34 dogs with non-tumor diseases,and 6 healthy dogs.Biochemical colorimetric assay were used to detect the serum TSGF level.Blood samples were collected at the time of initial diagnostic evaluation,before each chemotherapy session,and at follow-up visits.The serum TSGF level in dogs with malignant tumors,benign diseases,non-tumor diseases and healthy dog were 67.3±22.1 U/mL,57.3±7.58 U/mL,60.2±14.2 U/mL and 54.6±3.21 U/mL,the first group was statistically significant higher than the latter(P＜ 0.05).56.6％ malignant patients exceeded the upper limit of the normal reference range(61 U/mL).The samples were classified to groups according clinic stage.The TSGF level from malignant tumor groups were stage I 56.8 ±5.93 U/mL.stage Ⅱ 66.7±25.7 U/mL,stage Ⅲ 75.6±22.7 U/mL and stage IV 73.9±29.6 U/mL.Excluding stage Ⅰ,the TSGF level of all stages are statistically significant higher than healthy group,respectively,the stage Ⅲ was also statistically significant higher than stage Ⅱ.Further follow-up study indicated that in entirely insect group,the TSGF level decreased after treatment and kept in low level.In the partly insect group,although the TSGF activity decreased in a short term after surgery,the TSGF level would increase again and kept in high level.From this fact we considered that TSGF level is expected to be a newly potential biomarker in screening neoplastic diseases in veterinary and a monitoring factor for predicting relapse.