BACKGROUNDIn order to improve early detection, monitor disease outcome and find targets for more individualised therapy, there is an urgent demand for new biomarkers in oncology. A field of recent interest is clinical proteomics, which has been reported to lead to high sensitivity and specificities for early detection of several solid tumors [1,2] . This emerging field uses mass spectrometry-based protein profiles/ patterns of easy accessible body fluids to distinguish cancer from non-cancer patients. This would offer a solution to the problem of cancer often being diagnosed in late stages, when curative resection of the diseased organ is no longer possible and the disease has already metastasized, thus dropping survival rates dramatically. However, after the initial positive announcements in early 2002, criticisms were raised about several aspects of serum proteomics. In this paper we describe the hopes and fears for the introduction of clinical proteomics for early detection of Colorectal adenocarcinoma (CRC).
COLORECTAL CANCERColorectal adenocarcinoma is the third most common type of cancer and the fourth most frequent cause of death due to cancer worldwide. Worldwide almost one million new cases occur annually, amounting to 492 000 related deaths [3] . In developed countries it is the second most common type of tumor, with a lifetime risk of 5%, but its incidence and mortality is now decreasing [4,5] . Surgery is the cornerstone of therapy when the disease is confined to the bowel wall. This results in 70%-80% of patients who have tumors that, when diagnosed, can be resected with curative intent [6] . After curative surgery the five-year survival rate for patients with localised disease is 90%, decreasing to 65% in the case of metastasized disease to the lymph nodes. Adjuvant radiation therapy, chemotherapy, or both are useful in selected patients. Classification of tumors into pathogenetical subtypes with distinct clinical courses enables clinicians to target therapy. For CRC, the TNM staging system remains the gold standard and relies entirely on the morphological appearance of the tumor. However, tumors with similar histopathological characteristics may have different clinical outcomes and responsiveness to therapy [7] . Therefore, more individualised treatment would benefit the patient and may avoid unnecessary morbidity. Nonetheless, early detection of CRC will increase survival the most, in view of the fact that it is well recognized that CRC arises from a multistep sequence of genetic alterations that result
EDITORIAL
Current status and prospects of clinical proteomics studies on
AbstractColorectal adenocarcinoma (CRC) is the third most common type of cancer and the fourth most frequent cause of death due to cancer worldwide. Given the natural history of CRC, early diagnosis appears to be the most appropriate tool to reduce disease-related mortality. A field of recent interest is clinical proteomics, which was reported to lead to high sensitivity and specificities for early detection of several solid...