Potentials and challenges of chip technologies in serum biomarker studies for personalized medicine of colorectal cancer

More than 1.2 million new cases of colorectal cancer are reported each year worldwide. Despite actual screening programs, about half of the patients are diagnosed at advanced tumor stages presenting poor prognosis. Therefore, innovative screening tools could aid the detection at early stages and directly result in improving patient survival rates. An intriguing possibility for early cancer detection is represented by minimallyinvasive blood-based biomarker assays, indicating malignancy properties. It is not surprising that tremendous efforts have been taken to evaluate the serum proteome for its diagnostic value. However, the high variability of protein expression complicates the method of "proteomics". This might be one reason why single serum biomarkers for routine colon cancer screening have not been established so far. Against this background, the method of multiplex chip technology allowing simultaneous assessments of several biomarkers in a diagnostic panel has become of increasing interest, especially when considering limited clinical sample volume, costs, high-throughput, reproducibility, and the need for a more comprehensive description of molecular networks and pathophysiological conditions. Although some of the current multiplex chip biomarker studies are promising, strict quality management of samples and standard operation procedures have to become prerequisites in order to promote translational research. Recent data regarding patient inclusion, ethical permission, sample collection, sample processing and storage clearly show that a step forward must be taken for harmonization in standards for biomarker detection in order to be of use in clinical practice. In line, multiplex techniques could open the door to a more accurate and target specific personalized medicine.