MAPK8 and cleft palate: Since an ectopic condensed mesenchymal cell mass was observed in the posterior domain of each palatal shelf of E13.5 transgenic embryo (Fig. 2D) where ectopic pSmad1/5/8, P-p38, and P-JNK positive cells and expression of Shox2 and Msx1 were detected (Fig. 4; 5), we wondered if this condensed cell mass represents a condensation of precartilagious cells and the formation of ectopic cartilage within the palatal shelves could contribute to deformed palate morphology and subsequently to the cleft palate defect.