Abstract: Objective To detect the Alu expression in the stool of patients with pancreatic cancer and investigate its value in the diagnosis of pancreatic cancer.Methods Stool samples were obtained from patients with pancreatic cancer (PC) ( n =41 ),chronic pancreatitis (CP) ( n =27 ) and healthy subjects ( n =23 ),the DNA was extracted from the stool and the expression of Alu repetitive sequences was subjected to quantitative analysis by the real-time PCR.Results The expressions of Alu repetitive sequences in PC,CP,and healthy subjects were (5.17 ± 0.99 ),( 3.79 ± 0.94),(0.28 ± 0.35 ) rig/g,and the difference among the three groups was statistically significant (P <0.05).The AUC of PC was 74.8% with the 95% CI 0.661 ~0.835,and the sensitivity,specificity was 75.6% and 67.1%,respectively.Conclusions Alu repetitive sequences are highly expressed in the stool of patients with pancreatic cancer,and it is of value in the diagnosis of pancreatic cancer.