title: Identification of differentially expressed serum proteins in gastric adenocarcinoma.
abstract: Gastric adenocarcinoma is an aggressive cancer with poor prognosis. Blood based biomarkers of gastric cancer have the potential to improve diagnosis and monitoring of these tumors. Proteins that show altered levels in the circulation of gastric cancer patients could prove useful as putative biomarkers. We used an iTRAQ-based quantitative proteomic approach to identify proteins that show altered levels in the sera of patients with gastric cancer. Our study resulted in identification of 643 proteins, of which 48 proteins showed increased levels and 11 proteins showed decreased levels in serum from gastric cancer patients compared to age and sex matched healthy controls. Proteins that showed increased expression in gastric cancer included inter-alpha-trypsin inhibitor heavy chain H4 (ITIH4), Mannose-binding protein C (MBL2), sex hormone-binding globulin (SHBG), insulin-like growth factor-binding protein 2 (IGFBP2), serum amyloid A protein (SAA1), Orosomucoid 1 (ORM1) and extracellular superoxide dismutase [Cu-Zn] (SOD3). We used multiple reaction monitoring assays and validated elevated levels of ITIH4 and SAA1 proteins in serum from gastric cancer patients.
  
  
  CONCLUSIONS
  Gastric cancer is a highly aggressive cancer associated with high mortality. Serum-based biomarkers are of considerable interest in diagnosis and monitoring of various diseases including cancers. Gastric cancer is often diagnosed at advanced stages resulting in poor prognosis and high mortality. Pathological diagnosis using biopsy specimens remains the gold standard for diagnosis of gastric cancer. Serum-based biomarkers are of considerable importance as they are minimally invasive. In this study, we carried out quantitative proteomic profiling of serum from gastric cancer patients to identify proteins that show altered levels in gastric cancer patients. We identified more than 50 proteins that showed altered levels in gastric cancer patient sera. Validation in a large cohort of well classified patient samples would prove useful in identifying novel blood based biomarkers for gastric cancers. This article is part of a Special Issue entitled: Proteomics in India.
authors.affiliation: Institute of Bioinformatics, International Technology Park, Bangalore 560066, India; Rajiv Gandhi University of Health Sciences, Bangalore 560041, Karnataka, India; Department of Biochemistry, Kidwai Memorial Institute of Oncology, Bangalore 560029, Karnataka, India.
authors.forename: Yashwanth
authors.initials: Y
authors.lastname: Subbannayya
authors.affiliation: Institute of Bioinformatics, International Technology Park, Bangalore 560066, India; Manipal University, Manipal 576 104, Karnataka, India.
authors.forename: Sartaj Ahmad
authors.initials: SA
authors.lastname: Mir
authors.affiliation: Institute of Bioinformatics, International Technology Park, Bangalore 560066, India; School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 690525, India.
authors.forename: Santosh
authors.initials: S
authors.lastname: Renuse
authors.affiliation: Institute of Bioinformatics, International Technology Park, Bangalore 560066, India; Centre of Excellence in Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry 605014, India.
authors.forename: Srikanth S
authors.initials: SS
authors.lastname: Manda
authors.affiliation: Institute of Bioinformatics, International Technology Park, Bangalore 560066, India; Manipal University, Manipal 576 104, Karnataka, India.
authors.forename: Sneha M
authors.initials: SM
authors.lastname: Pinto
authors.affiliation: Institute of Bioinformatics, International Technology Park, Bangalore 560066, India.
authors.forename: Vinuth N
authors.initials: VN
authors.lastname: Puttamallesh
authors.affiliation: Institute of Bioinformatics, International Technology Park, Bangalore 560066, India.
authors.forename: Hitendra Singh
authors.initials: HS
authors.lastname: Solanki
authors.affiliation: Institute of Bioinformatics, International Technology Park, Bangalore 560066, India.
authors.forename: H C
authors.initials: HC
authors.lastname: Manju
authors.affiliation: Institute of Bioinformatics, International Technology Park, Bangalore 560066, India; Department of Biochemistry and Molecular Biology, School of Life Sciences, Pondicherry University, Puducherry 605014, India.
authors.forename: Nazia
authors.initials: N
authors.lastname: Syed
authors.affiliation: Department of Neurochemistry, National Institute of Mental Health and Neurosciences, Bangalore 560029, Karnataka, India.
authors.forename: Rakesh
authors.initials: R
authors.lastname: Sharma
authors.affiliation: Department of Neurochemistry, National Institute of Mental Health and Neurosciences, Bangalore 560029, Karnataka, India.
authors.forename: Rita
authors.initials: R
authors.lastname: Christopher
authors.affiliation: Department of Surgery, Kidwai Memorial Institute of Oncology, Bangalore 560029, Karnataka, India.
authors.forename: M
authors.initials: M
authors.lastname: Vijayakumar
authors.affiliation: Department of Surgery, Kidwai Memorial Institute of Oncology, Bangalore 560029, Karnataka, India.
authors.forename: K V
authors.initials: KV
authors.lastname: Veerendra Kumar
authors.affiliation: Institute of Bioinformatics, International Technology Park, Bangalore 560066, India.
authors.forename: T S
authors.initials: TS
authors.lastname: Keshava Prasad
authors.affiliation: Department of Biochemistry, Kidwai Memorial Institute of Oncology, Bangalore 560029, Karnataka, India.
authors.forename: Girija
authors.initials: G
authors.lastname: Ramaswamy
authors.affiliation: Department of Pathology, Kidwai Memorial Institute of Oncology, Bangalore 560029, Karnataka, India.
authors.forename: Rekha V
authors.initials: RV
authors.lastname: Kumar
authors.affiliation: Institute of Bioinformatics, International Technology Park, Bangalore 560066, India.
authors.forename: Aditi
authors.initials: A
authors.lastname: Chatterjee
authors.affiliation: McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Akhilesh
authors.initials: A
authors.lastname: Pandey
authors.affiliation: Institute of Bioinformatics, International Technology Park, Bangalore 560066, India. Electronic address: harsha@ibioinformatics.org.
authors.forename: Harsha
authors.initials: H
authors.lastname: Gowda
mesh_terms: D000230:Adenocarcinoma / Q000097:blood*; D014408:Biomarkers, Tumor / Q000097:blood*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D009363:Neoplasm Proteins / Q000097:blood*; D013274:Stomach Neoplasms / Q000097:blood*
chemical_list: D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins
keywords: Body fluid; In vitro labeling; LC-MS/MS analysis; Mass spectrometry; Serum proteome