The potential for markers of epithelial-mesenchymal transition to improve colorectal cancer outcomes: a systematic review.

Epithelial-mesenchymal transition (EMT) is thought to be an important mechanism of cancer cell metastasis. Clinical measurement of EMT markers in primary tumors could improve risk stratification and treatment decisions by identifying patients who potentially have metastatic disease. To evaluate the potential of EMT markers that could be used for risk stratification for patients with colorectal cancer, we conducted a systematic review of studies (N = 30) that measured at least one of a selection of EMT markers in primary tumors and patient outcomes. Fifteen of 30 studies (50%) reported at least one statistically significant result supporting a role for one of the selected EMT markers in identifying patients at risk for worse outcomes. Importantly, however, we identified design inconsistencies that limited inferences and prevented meta-analysis of data. We offer a number of recommendations to make future studies more informative and standardized, including consistent sampling of different parts of the primary tumor, larger sample sizes, and measurement of both protein and RNA expression of a given EMT marker in the same tumors. Strengthening the literature per our recommendations could facilitate translating EMT markers to clinical use. ©2014 American Association for Cancer Research.