SLIT-ROBO expression establishes two groups, which predict AFP expression levels in HCC cell lines. The means of normalized expression values of individual SLIT-ROBO genes in each cell line were used to establish the hierarchical clustering in Cluster program, and the results were visualized as a heatmap by TreeView. Overexpression and underexpression of individual genes relative to Ct average of all cell lines are represented by red and green colors, respectively. Upper single-row heatmap displays the average expression of all six genes across all cell lines. The tree at the top of the heatmap represents samplewise clustering. Based on their AFP expression levels, HCC cell lines are represented in two main subgroups indicated as Group I (low-AFP) and Group II (high-AFP) cells. The tree on the left of the heatmap (pink) represents genewise clustering.