Knockdown of FZD5 and FZD7 leads to a reduction in colony formation. NT2/D1 cells were individually infected with lentiviral shRNAs for FZD5, FZD7, or a control shRNA. Graphs depict a representative experiment performed in triplicate. a) FZD5 and b) FZD7 expression profiles were determined using real-time RT-PCRs. Results presented are an average of duplicate readings. c) The ability of the cells to form colonies when plated at a low density is shown. Error bars represent standard deviation. (* p < 0.05, **p < 0.005).