Relationship between the Presence of the R337H Mutation of the TP53 Gene and Expression of the p53 and p53R2 Proteins in Choroid Plexus Carcinomas

Background: The most common mechanism associated with the development of choroid plexus carcinoma seems to be mutation of the TP53 gene. The R337H mutation of the TP53 gene has been reported in a significant proportion of patients with choroid plexus tumors. The aim of the present study was to use immunohistochemical techniques to establish whether the presence of the R337H mutation is associated with changes in the expression of p53 and p53R2 in choroid plexus tumors. Methodology/Principal Findings: A total of 27 samples collected from patients with choroid plexus tumors were screened for p53 and p53R2 expression using immunohistochemistry; the results were compared as a function of the presence or absence of the R337H mutation. Immunopositivity for p53 was more frequent in patients with choroid plexus carcinomas than in patients with choroid plexus papillomas (p=0.006). All six cases of choroid plexus papilloma (100%) tested positive for the p53R2 protein. Patients with choroid plexus carcinomas that were immunopositive for p53R2 had higher odds of survival (p=0.041). The R337H mutation and tissue immunoexpression of p53 could be used in the differential diagnosis of atypical papillomas because both occurrences are strongly associated with choroid plexus carcinomas. The use of these factors would make it unnecessary for the World Health Organization (WHO) to maintain a category for atypical papilloma in their classification system. Some evidence points to an association between absence of the p53R2 protein and progression to death in cases of choroid plexus carcinoma. Significance: Our results show an additional biomarkers that can aid in the diagnosis, treatment and determination of the prognosis of patients with choroid plexus carcinoma will continue to drive future