In a xenograft model of human skin SCC, downregulation of TCF7L1 and its paralogue TCF7L2 decreased tumor size, indicating that these two LEF/TCF family members, whose functions overlap in skin development (Nguyen et al., 2006), are required for the optimal growth of xenografted tumors (Figure 3). The gene discussed is TCF7L1; the disease is neoplasm.