In recent years, significant progress has been made in identifying characteristic chromosomal and molecular rearrangements associated with several solid tumors. Most solid tumors studied have been found to be characterized by recurrent chromosomal abnormalities that are specific to histologic types. We have studied primary specimens of malignant melanoma, gastrointestinal cancer, renal carcinoma, lung and ovarian cancer, by cytogenetic and molecular means, and we discuss the genetic alterations found. Brief descriptions of the potential clinical utility, and biological relevance changes in these disorders are also discussed.