Abstract： Objective To investigate the expression levels of c-myc and PTEN in serum and tissue of patients with dia-betes mellitus complicated with pancreatic cancer and their relationship with prognosis.Methods 64 patients with pancreatic cancer were selected,of which 25 patients with simple pancreatic cancer were included in the control group and 39 patients with diabetes mellitus were included in the observation group.Serum c-myc and PTEN levels were detected by enzyme-linked immu-nosorbent assay.The expression of c-myc and PTEN proteins in cancer tissues was detected by immunohistochemistry.The expres-sion and survival of c-myc and PTEN in serum and tissues of the 2 groups were analyzed.COX multivariate regression analysis was conducted to analyze the prognostic factors of diabetic patients with pancreatic cancer.Results The serum c-myc level in the ob-servation group was higher than that in the control group,and the serum PTEN level was lower than that in the control group,P＜0.05;The positive rate of c-myc protein in the observation group was higher than that in the control group,and the positive rate of PTEN protein was lower than that in the control group,P＜0.05.The survival rate of c-myc(+)patients was lower than that of c-myc(-)patients,and the survival rate of PTEN(+)patients was higher than that of PTEN(-)patients,P＜0.05;Diabetes mellitus,positive expression of c-myc,positive expression of PTEN,tumor size,distant organ metastasis and differentiation degree were independent factors affecting the prognosis of pancreatic cancer patients(P＜0.05).Conclusion The expression levels of c-myc and PTEN are abnormal in serum and tissues of patients with diabetes complicated with pancreatic cancer.Positive expres-sion of c-myc is associated with poor prognosis,and positive expression of PTEN is associated with good prognosis.