Following the protein biomarker trail to colorectal cancer

Molecular Network of Colorectal Cancer and Current Therapeutic Options

Colorectal cancer (CRC), a leading cause of cancer-related mortalities globally, results from the accumulation of multiple genetic and epigenetic alterations in the normal colonic and rectum epithelium, leading to the progression from colorectal adenomas to invasive carcinomas. Almost half of CRC patients will develop metastases in the course of the disease and most patients with metastatic CRC are incurable. Particularly, the 5-year survival rate of patients with stage 4 CRC at diagnosis is less than 10%. Although genetic understanding of these CRC tumors and paired metastases has led to major advances in elucidating early driver genes responsible for carcinogenesis and metastasis, the pathophysiological contribution of transcriptional and epigenetic aberrations in this malignancy which influence many central signaling pathways have attracted attention recently. Therefore, treatments that could affect several different molecular pathways may have pivotal implications for their efficacy. In this review, we summarize our current knowledge on the molecular network of CRC, including cellular signaling pathways, CRC microenvironment modulation, epigenetic changes, and CRC biomarkers for diagnosis and predictive/prognostic use. We also provide an overview of opportunities for the treatment and prevention strategies in this field.

Progress in the identification of plasma biomarkers of colorectal cancer

Proteomic analysis of human tissue and plasma samples has been a useful tool in recent years for the identification of potential biomarkers to aid in the early diagnosis of colorectal cancer. However, biomarkers relating to the crucial transition between adenomatous lesions and invasive colorectal malignancy have not previously been described. The work of Choi et al. (Proteomics 2013, 13, 2361-2374) attempts to address this issue. Using plasma samples from age-matched patients with colorectal adenomas or invasive disease this group identified a range of plasma proteins and cytokines that were differentially expressed. This information not only provides insights into the biology of the adenoma to carcinoma progression sequence but it also represents a step towards the goal of achieving diagnostically accurate and clinically acceptable biomarkers in early colorectal cancer.