Epigenetic sampling effects: nephrectomy modifies the clear cell renal cell cancer methylome

Area of Science:

• Epigenetics
• Oncology
• Molecular Biology

Background:

• The impact of tissue sampling on the epigenome is not well understood.
• Understanding these effects is crucial for reliable epigenetic studies in cancer research.

Purpose of the Study:

• To investigate how artery ligation, a common surgical procedure, affects DNA methylation profiles in clear cell renal cancer.
• To determine the extent to which sampling procedures influence epigenetic alterations.

Main Methods:

• Compared DNA methylation profiles in vascularized tumor biopsy samples versus devascularized nephrectomy samples from two patients.
• Validated significant methylation changes in an independent clinical trial cohort.

Main Results:

• Identified six differentially methylated genes in test samples, with four linked to ischemia/hypoxia (REXO1L1, TLR4, hsa-mir-1299, ANKRD2).
• Confirmed significant differential methylation for three of these genes in the validation cohort, supporting the findings' authenticity.

Conclusions:

• Tissue ischemia induced during tumor removal can cause genuine epigenetic modifications.
• The influence of sampling procedures, especially those involving hypoxia/ischemia, must be considered in clinical epigenetic and translational cancer research.