Abstract: The study of genetic alterations in tumors and their precursor lesions is often hampered by the presence of a heterogeneous background of non-neoplastic elements such as stromal cells, inflammatory cells, and angiogenic elements. Microdissection involves the extraction of specific populations of cells under direct visualization. In this article, we will discuss the currently available techniques of microdissection, and briefly review how this material is being utilized in the study of cancer pathways. Microdissected tissue is amenable for the study of cancer genomics, expression analysis and most recently, cancer proteomics. The purity of reagents obtained from microdissected material has resulted in the successful identification of tumor suppressor genes as well as novel transcripts and proteins that are altered in neoplastic cells. Improved techniques of tissue fixation and microdissection, supplemented with ancillary technology such as pre-amplification, have permitted the use of increasingly smaller quantities of material for the study of cancer pathways. Importantly, it is now possible to analyze many of the genetic changes that precede cancer, thereby identifying populations "at risk" for developing malignancies in the future.