ANALYSIS OF DNA MISMATCH REPAIR PROTEINS IN HUMAN MEDULLOBLASTOMA

During replication, the primary function of the eukaryotic DNA mismatc h repair (MMR) system is to recognize and correct mismatched base pair s within the DNA helix. Deficiencies in MMR have been reported previou sly in cases of hereditary nonpolyposis colorectal cancer and sporadic tumors occurring in a variety of tissues including gliomas, Furthermo re, recent evidence indicates that the MMR system may be involved in m ediating therapeutic sensitivity to alkylating agents. In this study, 22 neoplastic tissue samples from 22 patients who underwent surgical r esection for medulloblastoma, a common cerebellar tumor of childhood, were assayed for the presence or absence of MMR polypeptides using Wes tern blot and immunohistochemical techniques. Results from these exper iments indicate that the MMR system is not commonly deficient in medul loblastoma.