MRC1 and neoplasm: Accurate classification of the parental tumors and PDXs into molecular subgroups cannot be performed, since mismatch repair protein (MMR) IHC was only conducted for a limited number of proteins, e.g., PMS2 and MSH651; however, MMR IHC abnormality was noted in the parental tumor, and it was maintained in PDXs of case UXE-010.