Multiplex genotype analysis of invasive carcinoma and accompanying proliferative lesions microdissected from breast tissue

To understand the genetic basis of breast cancer in a comprehensive way, pu rported precursor lesions need to be analyzed at a large number of genetic marker loci and compared with each other and with the invasive components. However, the microscopic size of most of these lesions and the very small a mount of material that can be obtained through microdissection limit the nu mber of loci that can be included in the analysis. To address this issue, a multiplex genotyping approach has been developed. With this approach, poly morphic sequences at 28 marker loci were amplified simultaneously from the microdissected components in 5-mu m paraffin-embedded breast tissue section s. The genotypes of the lesions were determined after resolving the amplifi ed allelic products by denaturing gradient gel electrophoresis. Because the material isolated from each lesion in a single 5-mu m section was sufficie nt for several 28-locus assays and several successive tissue sections with the same set of lesions may be prepared, it is possible to determine the ge notype of each lesion at hundreds of genetic marker loci that may well cove r the human genome. Analyzing a sufficient number of cases may yield inform ation that could be used to understand the genetic basis of breast cancer d evelopment in a comprehensive way.