Studies demonstrate that the serum level of cytokeratin 19 fragment antigen 21-1 ( CYFRA21-1 ) is high in various cancer types.As a novel epithelial cells derived tumor marker,detection of the serum level of CYFRA21-1 is of great clinical significance for screening and diagnosis,curative effect evaluation,recurrent monitoring and prognosis assessment for cancer patients.

Numerous studies found that the content of peripheral blood circulating RNA in various cancer types is aberrant increased,which could be a potential biological diagnostic marker and therapeutic target.Detecting the peripheral blood circulating RNA through the molecular biology technology will provide a sensitive and efficient,convenient,specific,noninvasive and minimally invasive therapy for the early diagnosis and detection,prognosis and therapeutic monitoring of malignant tumor.

Objective To evaluate the diagnostic value of the combination of serum DKK1 (Dickkopf-1 )and P53 autoantibodies in patients with esophageal squamous cell carcinoma (ESCC).Methods Serum levels of DKK1 and P53 autoantibodies were measured by enzyme-linked immunosorbent assay (ELISA) for the 1 26 patients with ESCC and 60 normal controls.Receiver operating characteristics (ROC)was used to calculate the diagnostic efficiency.Results The serum levels of DKK1 and P53 autoantibodies were signifi-cantly higher in ESCC than those in normal controls [(673.09 ±343.82)pg/ml vs (362.05 ±1 48.07)pg/ml, Z =6.1 58,P <0.000 1 ;(0.398 ±0.546)vs (0.069 ±0.050),Z =3.832,P <0.000 1 ].ROC curves showed the optimum diagnostic cutoff for serum DKK1 was 588.77 pg/ml,with an area under curve (AUC)of 0.780 (95%CI:0.71 5 ~0.844,61 .9% sensitivity,95.0% specificity).Measurement of P53 autoantibodies demonstrated an AUC of 0.674 (95%CI:0.598 ~0.750,45.3% sensitivity,95.0% specificity).The com-bination of DKK1 and P53 autoantibodies yielded an AUC of 0.843 (95%CI:0.788 ~0.897,73.8% sensitiv-ity,95.0% specificity).In early-stage ESCC,combined detection of DKK1 and P53 autoantibodies improved the diagnostic power,with an AUC of 0.903 (95%CI:0.845 ~0.961 ,81 .0% sensitivity,95.0% specifici-ty).Conclusion Serum DKK1 and P53 autoantibodies can be used as potential diagnostic biomarkers for the ESCC.Combined detection of them might aid the early diagnosis of ESCC.