CD9 and cancer: Consistent with this, analysis of data obtained from the Cancer Cell Line Encyclopedia[28] (http://www.broadinstitute.org/ccle/home) of 47 colon cancer cell lines for mRNA expression reported as a robust multi-array average (RMA) of CDCP1 and CD9 showed a highly significant positive correlation (p = 0.0001) between CDCP1 and CD9 mRNA expression by Pearson correlation analysis (Figure 2D).