# Clinical utility of DNA methylation profiling for choroid plexus tumors

## TL;DR

DNA methylation profiling helps better predict the aggressiveness of choroid plexus tumors compared to traditional microscopic analysis.

## Contribution

DNA methylation profiling is shown to provide more accurate prognostic information for choroid plexus tumors than WHO histologic grading alone.

## Key findings

- Methylation class correlated with WHO histologic grade in 92% of choroid plexus carcinomas.
- Five choroid plexus papillomas grouped with methylation class of carcinomas, indicating potential aggressiveness.
- Methylation profiling improved prediction of tumor behavior and patient outcomes.

## Abstract

Choroid plexus tumors (CPTs) are rare, potentially aggressive CNS tumors with defined histologic criteria for grading. In recent years, several patients within our practice have demonstrated discordance between the histologic diagnosis and clinical behavior. DNA methylation profiling has emerged as a potential diagnostic adjunct for aiding the clinical approach.

We reviewed the clinical and pathologic data of all CPTs diagnosed at Boston Children’s Hospital from 1995 to 2023. All cases with available material (38/48) underwent DNA methylation profiling at NIH/NCI, and the classifier results were correlated with the WHO histologic grade and patient outcomes. Survival information was analyzed using Kaplan–Meier curves.

There was good correlation (11/12, 92%) between methylation class and WHO histologic grade for choroid plexus carcinomas (CPC); one histologic CPC grouped with choroid plexus papilloma (CPP) group pediatric (P). Five CPPs grouped with methylation class CPC (5/17, 29%). In the group of atypical CPPs (n = 9), there were two that grouped with methylation class CPC. Survival analysis showed utility of methylation classes in the prediction of biologic behavior.

Results indicated that methylation profiling may serve as a valuable tool in the clinical decision-making process for patients with CPTs, providing additional prognostic information compared to WHO histologic grade alone. The value of methylation array analysis is particularly important given the lack of consensus on treatment regimens for CPTs.

Choroid plexus tumors are rare brain tumors that can be aggressive. Usually, these tumors are diagnosed by examining the tumor under a microscope after surgery. However, this method can sometimes be inaccurate because the appearance of the tumor under the microscope doesn’t always match its aggressiveness. The authors of this study wanted to see if genetic techniques, specifically DNA methylation profiling, could be used to diagnose these tumors and predict their aggressiveness more accurately. To do this, they studied 38 patients with choroid plexus tumors treated at one hospital between 1995 and 2023. They compared traditional microscopic appearance with DNA methylation profiling. Their results showed that DNA methylation profiling generally agreed with the microscopic analysis, but in some cases, it provided additional information that better predicted how aggressive the tumor would be.