To discover and confirm blood-based colon cancer early-detection markers. Dr Paul Lampe and colleagues from Washington, USA created a high-density antibody microarray to detect differences in protein levels in plasma from individuals diagnosed with colon cancer <3 years after blood was drawn and cancer-free, matched controls.
Potential markers were tested on plasma samples from people diagnosed with adenoma or cancer, compared with controls.
Components of an optimal 5-marker panel were tested via immunoblotting using a third sample set, luminex assay in a large fourth sample set and immunohistochemistry on tissue microarrays.
In the prediagnostic samples, the researchers found 78 significantly increased proteins, 32 of which were confirmed in the diagnostic samples.
From these 32, optimal 4-marker panels of BAG family molecular chaperone regulator 4, interleukin-6 receptor subunit beta, von Willebrand factor and CD44 or epidermal growth factor receptor were established.
|The protein/glycoprotein panel was significantly higher in
colon cancer samples
The researchers found each panel member and the panels also showed increases in the diagnostic adenoma and cancer samples in independent third and fourth sample sets via immunoblot and luminex, respectively.
Immunohistochemistry results showed increased levels of BAG family molecular chaperone regulator 4, interleukin-6 receptor subunit beta and CD44 in adenoma and cancer tissues.
The team noted that inclusion of epidermal growth factor receptor and CD44 sialyl Lewis-A and Lewis-X content increased the panel performance.
The protein/glycoprotein panel was statistically significantly higher in colon cancer samples, characterised by a range of area under the curves from 0.90 to 0.86, for the larger second and fourth sets, respectively.
Dr Lampe's team concluded, "A panel including BAG family molecular chaperone regulator 4, interleukin-6 receptor subunit beta, von Willebrand factor, epidermal growth factor receptor and CD44 protein/glycomics performed well for detection of early stages of colon cancer and should be further examined in larger studies."