Novel translational strategies in colorectal cancer research

Association of a characteristic membrane pattern of annexin A2 with high invasiveness and nodal status in colon adenocarcinoma

The identification of tumor cells in lymph nodes is essential for the correct classification of patients with colorectal cancer who may benefit from adjuvant treatments. Proper classification of tumor stage becomes entangled by variables such as an insufficient number of lymph nodes examined, which can result in erroneous or missed diagnosis. The determination of pathologic factors in the primary tumor associated with positive lymph nodes is an area of research that has attempted to provide variables to solve this problem. In the present study, we observed that the localization of annexin A2 (AnxA2) in a cell membrane is the characteristic that distinguishes tumor cells with high invasiveness. Localization of AnxA2 expression was also studied in tissue specimens from 58 patients with invasive colorectal carcinoma (T3-T4), who had undergone colectomy with radical lymph node dissection. Interestingly, the membrane pattern observed in tumor cell lines was also identified in patient's tissue samples and allowed us to distinguish among different cell populations with the tumor. Univariate analysis showed that tumor deposits in pericolic fat, extramural vascular invasion, and amount of cells with AnxA2 membrane pattern in the tumor invasive edge had a significant influence on lymph node metastasis. On the contrary, multivariate analysis revealed that the number of cells with AnxA2 membrane pattern (P < 0.05) and tumor deposits (P < 0.05) was significantly associated with lymph node metastasis. Furthermore, AnxA2 cellular localization was observed in cell clusters that define tumor budding, and a significant association between both variables was detected.

Cell surface markers in colorectal cancer prognosis

The classification of colorectal cancers (CRC) is currently based largely on histologically determined tumour characteristics, such as differentiation status and tumour stage, i.e., depth of tumour invasion, involvement of regional lymph nodes and the occurrence of metastatic spread to other organs. These are the conventional prognostic factors for patient survival and often determine the requirement for adjuvant therapy after surgical resection of the primary tumour. However, patients with the same CRC stage can have very different disease-related outcomes. For some, surgical removal of early-stage tumours leads to full recovery, while for others, disease recurrence and metastasis may occur regardless of adjuvant therapy. It is therefore important to understand the molecular processes that lead to disease progression and metastasis and to find more reliable prognostic markers and novel targets for therapy. This review focuses on cell surface proteins that correlate with tumour progression, metastasis and patient outcome, and discusses some of the challenges in finding prognostic protein markers in CRC.