Expression of Wnt pathway genes (such as FZDI, FZD3, FZD4, FZD5, FZD6 and SFRP1, SFRP2, FRZB, SFRP4) have been previously reported in a pluripotent human embryonal carcinoma cell line and in an embryonic stem cell [15], which supports the reliability of our functional module analysis. Here, FZD4 is linked to embryonal carcinoma.