In this paper, we use three gene ranking techniques including two new methods based on a single gene score approach and support vector machine (SVM) method based on recursive feature elimination (RFE). These methods have been evaluated on colon cancer dataset by gene ontology. Experimental results showed that these methods select genes that do not have any GO. So, great parts of data that have GO are deposited. With having GO, we can gain a better understanding of the data than just applying statistical analysis because biological significance does not necessarily have to be statistically significant. We propose to enter biological knowledge into gene selection process. Using GO prevents from producing spurious results