To test this, we overexpressed the L366K and L411K mutants, and BCL9 and BCL9-2 mutants with small internal HD1 deletions (ΔHD1), as well as ΔHD1 L366K and ΔHD1 L411K double-mutants in colorectal cancer cells, and we examined their effects on the Wnt pathway activity of these cells by using TCF reporter activity (TOPFLASH) as a specific and quantitative read-out [39]. Here, BCL9 is linked to colorectal cancer.