Mutation Analysis of Large Genomic Regions in Tumor DNA Using Single-Strand Conformation Polymorphism: Lessons from the ATM Gene

In recent years, we have seen a dramatic improvement in our ability to detect nucleotide changes in tumor DNA using a number of techniques for mutation detection that have become routine instruments in many laboratories. The choice of a suitable method or methods of mutation analysis is governed by many factors, including the costs, experimental sensitivity, expected mutation pattern in the target sequence and its functional consequences, as well as staff expertise, personal experience, and preference. The primary selection criterion for such a method is the ability of a technique to search for the presence of unknown mutations in the analyzed regions (scanning methods) as opposed to looking for known mutations already characterized at the nucleotide level. Scanning procedures represent a cost-effective alternative to nucleotide sequencing (see Chapter 13 ), but usually at a price of an inferior detection rate. The former group of techniques includes procedures based on conformation polymorphism changes, denaturing gradient gel electrophoresis (see Chapter 10), constant denaturant capillary electrophoresis, and mismatch repair and RNase cleavage methods (see Chapter 11). The latter group, exemplified by techniques using sequence-specific oligonucleotides, oligonucleotide liagation assay, and ligase chain reaction (1), is less frequently used for analyzing molecular changes in tumor samples. A wise choice of most appropriate procedures is a crucial step for the identification of molecular changes underlying cancer development and for the correct interpretation of mutation screening