Nucleic acid hybridization (NAH), an extremely important molecular biology research tool, has the potential to be a major diagnostic procedure. However, the current technique requires the use of expensive, hazardous and time consuming methods based on radioactive materials. Furthermore, NAH tests typically result in either non-quantitative or only semi-quantitative information, a serious limitation when it is important to know if an abnormal quantity of a sequence (e.g. oncogenes) is present. A new non-isotopic labeling procedure which takes less than 1 hour, requires less toxic and less expensive reagents, appears more reliable, and has sensitivity which is higher than previous methods has been implemented in preliminary experiments. An improved method for quantitating radioactive and non-isotopic hybridizations based upon computerized image processing has also been developed. A Phase I grant will permit us to: (1) test this labeling technique on nucleic acids from transformed cells to determine the feasibility of using this technique in clinical medicine; and (2) quantify the extent of hybridizations using a prototype image processing system. In Phase II, we will use these systems for the analysis and quantitation of oncogenes, potentially oncogenic viruses, and chemotherapy resistance in a variety of cell lives and clinical specimens.