Metadata supporting data files in the published article: The acute effects of adjuvant radiation and chemotherapy on peripheral blood epigenetic age in early stage breast cancer patients

In this
study, the authors examined epigenetic changes in peripheral whole blood cells
in early stage breast cancer (BC) patients undergoing surgery followed by
adjuvant radiotherapy, or surgery followed by adjuvant chemotherapy and
radiotherapy.

Data access:
The dataset RISEdataTab1.xlsx supporting Table 1 of the published article is publicly available in the figshare repository as part of this data record.
Methylation data supporting Figure 1 and Supplementary Figure 2 of the published article are publicly available in the Gene Expression Omnibus repository, via accession https://identifiers.org/geo:GSE140038. The filenames and types are as follows: NormalizedBetaNoob.csv, GSM4151814-GSM4151957 (in idat format), and Data Dictionary.docx.

Study approval and patient consent:
This
study was approved by the UCLA Medical Institutional Review Board. Informed
consent was obtained from all participants.

Study aims and methodology:
The aim
of this study was to examine the acute effects of adjuvant radiation and
chemotherapy on peripheral blood epigenetic age in early stage breast cancer
patients.

Women were eligible for the study if they
had been recently diagnosed with Stage 0-IIIA BC and had not yet started
adjuvant or neoadjuvant therapy with radiation, chemotherapy, or endocrine
therapy. Assessments were conducted before onset of adjuvant therapy, after
completion of radiation and/or chemotherapy, and over an 18-month follow-up.
The current analysis focuses on a subset of women (n=72) who had blood samples
available for epigenetic analyses at baseline and post-treatment. The women
selected were treated with radiation alone (n=37), and with chemotherapy
followed by radiation (n=35), to evaluate individual and combined effects of
those treatment exposures. All women had completed surgery prior to the
baseline assessment.

Four measures of epigenetic age
acceleration were examined: intrinsic (IEAA), extrinsic (EEAA), phenotypic (PEAA),
and Grim (GEAA), based on weighted averages of methylation levels at 353, 71,
513, and 1,030 CpGs, respectively, with adjustment for chronologic age.

Details of the epigenetic clock, DNA
extraction/methylation experiments, and statistical analyses are provided in the
supplementary methods.