Novel Candidate Protein Biomarkers Identified for Gastric Cancer

The early detection of stomach or gastric cancer (GC) has been revealed with the identification of four new biomarkers in the blood of human cancer patients.

This poor outcome of GC can be attributed to an extended asymptomatic period associated with this cancer, and difficulty in the detection of early stage gastric adenocarcinoma when treatment could improve long term survival of patients.

Scientists at the University of Adelaide (Australia) collected serum samples from 37 preoperative GC patients with intestinal type gastric adenocarcinoma. There were 10 females, with a mean age range of 69 ± 10 years and 17 males with a mean age range of 66 ± 11 years. In the cohort were 11 early stage cancer patients, and the controls included healthy and noncancerous patients with other gastric disease.

Enzyme-linked immunosorbent assays (ELISA) were performed for four proteins afamin, clusterin, haptoglobin and vitamin D binding protein (VDBP) and obtained from USCN Life Science Inc., (Wuhan, China). Ten GC and 10 controls serum samples were analyzed with multiple reaction monitoring high resolution mass spectrometry (MRM-HR). These serum samples were run on Triple TOF 5600 mass spectrometer (AB Sciex; Framingham, MA, USA) with an Ultra nano-liquid chromatography (LC) system (Eksigent; Redwood City, CA, USA).

The analysis of the ELISA results showed that the sensitivity and specificity values represented as Area Under the Curve (AUC) were: 0.94 for clusterin, 0.84 for VDBP, 0.58 for haptoglobin, and 0.52 for afamin. The MRM-HR data when analyzed revealed a trend for differential regulation of afamin, clusterin and VDBP. MRM-HR analysis revealed a significant higher abundance of haptoglobin in GC patients which was similar to that observed in the results from the ELISA. All four proteins were individually superior to a current clinical marker CA72-4 in discriminating stomach cancer from healthy controls.

The authors concluded that the differential regulation of four serum proteins in gastric cancer patients compared with normal healthy individuals were found with clusterin, VDBP and afamin down-regulated, and haptoglobin up-regulated in serum from GC versus benign GI disease cases. Peter Hoffmann, PhD, a professor at the University of Adelaide and senior author of the study said, “Stomach cancer is typically without symptoms in the early stages so most cancers are not diagnosed until the later stages, and the survival rates are therefore low. A noninvasive, inexpensive screening technique through a simple blood test for the early detection of stomach cancer would make a huge difference in the survival outcomes for people with this disease.” The study was published on February 7, 2014, in the journal Biochimica et Biophysica Acta.

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