The Alani Lab has had a long-standing interest in investigating the role of Id helix-loop-helix transcription factors in regulating cell growth and differentiation. Studies from our group have identified important roles for Id transcription factors in regulating the development of tumor-associated vessels and in the development of malignant melanoma. To date, we have been able to identify several important mediators of Id gene effects on tumor-associated angiogenesis including the angiogenesis inhibitor, thrombospondin-1. We have also determined that the mechanisms of tumor-associated angiogenesis for tumor xenografts and autochthonous tumors occur through divergent processes that are Id-dependent and involve bone marrow-derived cells in the former case and Id-independent involving recruitment of endothelial cells from neighboring vessels in the latter case. Current studies in the lab will determine the specific role of Id1 target genes in bone marrow-derived tumor angiogenesis. We are also interested in defining the molecular determinants of melanoma development and progression and have published some exciting early studies on the role of Id1 in this process. Current efforts in the lab are focused on defining the role of Id1 in melanoma development and its utility as a tumor marker and therapeutic target for this deadly form of skin cancer. Additional studies in melanoma using gene expression profiling of tumors from varying stages of malignant progression have yielded some exciting preliminary data which will likely lead to additional novel tumor markers and therapeutic strategies.