Gene expression of Wnt ligands and Frizzled receptors in human EC cells. Real-time RT-PCR arrays were used to determine the gene expression profiles of Wnt ligands and Fzd receptors in NT2/D1 cells relative to housekeeping genes. Graphs represent averages and standard deviations of at least 3 independent RNA samples. Graphs depict the gene expression profiles of a) Wnt ligands and b) Fzd receptors in NT2/D1 cells treated +/- RA for 4 days. (* p < 0.05, **p < 0.005).