LEF1 and neoplasm: Because LEF1/TCF is a transcriptional downstream effector of Wnt/ β-catenin signaling and its expression is associated with poor prognosis, Elizabeth Lawlor speculated about intra-tumor heterogeneity of EWS-FLI1 expression and the role of the tumor micro-environment in activating Wnt/ β-catenin and its role in promoting tumor cell motility and metastasis.