1. Introduction
Globally more than 1.2 million new cases of colorectal cancer (CRC) are reported every year resulting in ~600,000 deaths [1]. Therefore, CRC is a major cause of cancer morbidity and mortality worldwide. The risk to get CRC rises with increasing age: 90% of new cases occur in people who are 50 years or older. On average, the individual risk for CRC is about 1 in 20, although this varies widely according to individual risk factors i.e., intestinal polyps. The basis for all molecular analyzes of CRC is the exact definition of the affected tissue and subsequently the microdissection of an area enriched in tumor cells (Figure 1). The prognosis of survival is dependent on the stage of disease at diagnosis. CRC is divided into Union for International Cancer Control (UICC) stage I–IV cancers. Patients with UICC stage I colon cancer have an excellent 5-year survival rate of 90%, UICC stage II cancer patients present a survival rate between 70%–90%, whereas the 5-year survival rate decreases to 30%–90% in patients with UICC stage III tumors [2,3]. Adjuvant therapy is widely considered the standard of care in patients with UICC stage III CRC. However, the role of this therapy is controversial in stage II patients because the overall benefit is small [3].
Figure 1  Colorectal cancer specimen, intermediate grade, showing invasion of Tunica muscularis. Insert: Labelled area defines tumor cells for manual microdissection. H&E stain, 20× magnification.   This review article summarizes the current status and the perspectives of clinical applications of predominantly microarray-based assays in colorectal cancer. There are many promising applications which will support early detection and targeted therapies in colorectal cancer. They are summarized in Table 1. Subdivisions of these potential applications are based on various molecular states found in CRC that could serve as a basis for CRC clinical diagnostics. Application of these novel diagnostics tests may lead to an advancement of targeted therapies in personalized CRC oncology. Examples of developing commercially available assays are also discussed.
microarrays-03-00168-t001_Table 1 Table 1  Overview of molecular biology tests used in colorectal cancer (CRC) diagnostics.   CIMP = CpG island methylator phenotype, FFPE = formalin fixed paraffin embedded, IHC = immunohistochemistry, miRNA = micro ribonucleic acid, MSI = microsatellite instability, PCR = polymerase chain reaction.

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