Current concepts in quantitative molecular hybridization.

Knowledge of the molecular biology of cancer and other diseases has grown enormously in the past decade. The role certain genes play in disease states is clearer, creating new opportunities for diagnostic applications of molecular biological techniques in clinical medicine. The measurement of an abundance of certain nucleic acids could be valuable as a diagnostic or prognostic test. For example, aberrant expression of growth-promoting genes has correlated with the type and severity of certain neoplasias. Also, the determination of an abundance of exogenous sequences, arising from viruses or other pathogens, can be useful for evaluating virus load and activity during infection. Changes in the levels of these sequences could provide a means to determine the efficacy of therapy. Nucleic acid sequences can be measured by molecular hybridization using complementary nucleic acids as probes. Strategies for performing quantitative molecular hybridization, and their application in the clinic, are discussed.