Frequency and prognostic impact of microsatellite instability in a large population-based study of endometrial carcinomas

The replication error repair (RER) phenotype has been reported in 9-43% of sporadic endometrial carcinomas, but there are conflicting data about its e ffect on prognosis in this disease, This study was performed to establish t he frequency of the RER phenotype and to determine its effect on prognosis in a population-based series of 259 endometrial carcinomas with Long-term f ollow-up. Five mononucleotide and dinucleotide microsatellite markers on di fferent chromosomes were analyzed, and tumors exhibiting microsatellite ins tability at two or more loci were classified as RER+, A total of 116 of 259 tumors (45%) were RER+, The 5-year survival rate for the RER- group was 76 .2% compared with 79.6% for RER+ cases (P = 0.6), The 5-year recurrence-fre e survival rate among the 228 patients surgically treated for cure was 80.6 % in the RER- group compared with 83.6% in the RER+ group (P = 0.6), The an alysis indicates that the RER phenotype is common in endometrial carcinomas , but there is no association with prognosis in this large population-based series of endometrial carcinomas.