Overview of principles and current uses of DNA probes in clinical and laboratory medicine.

Fundamental considerations of deoxyribonucleic acid (DNA) probe hybridization reaction including concept of stringency is reviewed. Restriction fragment length polymorphism (RFLP) and its detection using DNA probes are discussed together with the importance of RFLP in genetic linkage analysis. Methodological considerations, such as limitations in sample preparation and improvements effected in techniques, cloning DNA, and labelling of DNA probes, are addressed. Principles of hybridization technology and blotting techniques are reviewed. Amplification of DNA by the polymerase chain reaction (PCR), labelling with PCR, detection of PCR products and separation procedures prior to use of PCR are discussed. Other amplification methods and in-situ hybridization (ISH) procedures are reviewed. Selected current applications of DNA probes in the area of infectious diseases, genetic diseases, HLA typing, paternity and forensic testing are briefly discussed. Emphasis is placed on the use of DNA probes in the area of oncology. Background on activation of proto oncogene, loss of tumor suppressor genes, chromosomal translocation, and chromosome analysis are provided for understanding DNA probe assays for ph1 positive leukemias and applications of Interphase cytogenetic technique in oncology. Finally, analytical strategies for detection of tumor suppressor genes are addressed.