A. M. Goss et al. from the University of Pennsylvania reported in the August issue of Developmental Cell the results of their study on Wnt signaling for specifying lung endoderm progenitors within the anterior foregut of mouse embryos. The experimental data revealed that embryos lacking Wnt2/2b expression were not able to develop lungs nor did the cells in the foregut express NKx2.1, a marker for lung endoderm. However, embryos with the mutation were able to specify other endoderm-derived organs such as the thyroid, liver, and pancreas. β-catenin expression is also inhibited in cells of the foregut lacking Wnt2/2b signaling. This observations demonstrates that Wnt2/2b signaling is through the canonical Wnt pathway which is required for specifying lung endoderm progenitors during lung gensis within the foregut. The investigators also showed that activation of canonical Wnt/β-catenin signaling can result in reprogramming esophagus and stomach endoderm to a lung endoderm progenitor fate. The authors concluded that "Wnt2/2b signaling is required for the specification of lung endoderm progenitors in the developing foregut."