JAK/STAT signaling facilitates vital developmental processes in a diverse array of mammalian and invertebrate species. One such species, Drosophila melanogaster, appears to be a strong candidate for investigating and modeling mechanisms for early morphogenetic changes common to both humans and fruit flies. Of particular interest are the potential roles that signaling pathways implicated in invasive growth patterns, such as JAK/STAT, serve in oncogenesis and metastasis of tumors. In Drosophila, progenitors of adult air sacs, which supply oxygen to flight muscles, are known as air sac primordia (ASP), and function in a manner comparable to human lungs. Because these ASP propagate into wing imaginal discs invasively, we have begun investigating possible roles that JAK/STAT signaling proteins might play in the directed morphogenesis of these structures. Our current research focuses on enhancing or suppressing expression of three components in the JAK/STAT signaling cascade of Drosophila: the JAK (hopscotch), ligand receptor (domeless), and STAT (Stat92e).