Screening For New Tumor Markers Of Pancreatic Cancer Using Secretome Analysis

Backgroud&Aims PDAC has been known as the most lethal cancer,its mortality is equal to its incidence. PDAC is insensitive to chemotherapy and radiotherapy,and radical excision is the only hope to cure this disease.Unfortunately, due to the difficulty to make early diagnosis for PDAC, most patients suffering from PDAC are local advanced stage and have no chance for surgery when they come to the hospital.In order to enhance the treatment effectiveness,it is urgent to make early diagnosis more easily.Tumor marker is an useful method for early diagnosis,and CA19-9is the most excellent tumor marker for PDAC at present,but it is still unsatisfactory.After development of several decades, proteomics is widely used in searching for tumor markers.Our research purpose is to find some more effective tumor markers for PDAC and establish specific secretome dateset of PDACMethods We use serum-free culture media to culture2PDAC tissues and4normal pancreatic tissues.Then we collect and concentrate culture solution to get secreted proteins.After that,Shotgun Liquid chromatography tandem mass spectrometry and High-difenition mass spectrometry, these two different proteomic research methods were used to analysis secreted proteins and establish the specific secretome dateset of PDAC.Then we test the serumlevels of ApoA-Ⅱ and ApoC-Ⅰ in69PDAC cases,32diseases control cases,21health volunteer cases using ELISA.We analysis the results of ELISA and judge the potential ability of ApoA-Ⅱ and ApoC-Ⅰ to be tumor marker.Results We analysis three secreted proteins samples using Shotgun Liquid chromatography tandem mass spectrometry method for three times, and110,5and9secreted proteins are identified for each sample. And then we analysis four secreted proteins samples using High-difenition mass spectrometry method,515,252,89and179secreted proteins are identified for each sample.After removing the repetitive proteins,we get570specific secreted proteins of PDAC. Then we test the serumlevels of ApoA-Ⅱ and ApoC-Ⅰ in69PDAC cases,32diseases control cases,21health volunteer cases using ELISA,the result shows there is no significant difference of the average ApoA-II serumlevels between PDAC group and health volunteer group (P>0.05),and the average serumlevels of ApoC-I is higher in69PDAC cases than in21health cases (P<0.05) The cut-off value of ApoC-I is21.69μg/ml, and its sensitivity and specificity is76.2%and57.1%respectively. Combination of ApoC-I and CA19-9for diagnosising PDAC could enhance the sensitivity and specificity to95.59%and84.38%respectively.Conclusion Secreted proteins dateset is different between PDAC group and health volunteer group. PDAC tissues can produce specific secreted proteins into the culture solution that could be identified by mass spectrography analysis. Serumlevels of ApoA-Ⅱ has no significant difference between PDAC and health volunteer group. And the average serumlevels of ApoC-Ⅰ is higher in PDAC,which indicated ApoC-Ⅰ can be used as tumor marker of PDAC.