[Assessment of malignant grade of colorectal cancer]

In recent years, colorectal cancer has become a very common malignancy in Japan. In the treatment strategy for each patient with colorectal cancer, the evaluation for malignant grade, represented as a recurrence rate, prognosis, etc., is very important. Various biological and/or molecular factor(s) have been investigated in terms of the relationship to malignant phenotype and its predictive value of prognosis, however, none of them has been proved to be clinically useful so far. Recently, several markers have been shown to be useful as the predictive marker for recurrence, especially in Stage II/III colorectal cancer. Among them, microsatellite instability (MSI), gene expression profile analysis, and micro RNA as a topic are briefly introduced in this minireview.