Rapid identification of patient specimens with microsatellite DNA markers

Despite the use of standardized clerical and processing procedures in surgical pathology, questions might arise regarding the proper identification of specimens with respect to patient source. Genotypic analysis of microsatellite DNA polymorphisms was used to identify the patient source of two surgical pathology specimens showing carcinoma. Four highly polymorphic microsatellite loci were evaluated in DNA extracted from various formalin-fixed, paraffin-embedded tissues. Using this technique, we determined that the diagnosis of poorly differentiated adenocarcinoma arising from a background of colitis had been assigned to the correct patient, despite the fact that multiple repeat endoscopic examinations, with biopsy specimens, were negative. In the second case, a suspected processing error involving the exchange of specimen accession numbers was resolved when a lymph node containing a microscopic focus of metastatic carcinoma was assigned to the appropriate patient. A multitude (approximately 50,000 to 100,000) of microsatellite loci are distributed throughout the human genome, and many are highly polymorphic. Hence, genotypic analysis using microsatellite loci has a significantly higher power of discrimination than other commonly used methods. The technique is rapid and is particularly well suited to the analysis of small, fixed-tissue specimens.