Epigenomics may begin to explain in vitro differential response to hypomethylating agents in MMR-D hypermethylated endometrial cancer

Epigenomics. 2023 Mar;15(5):283-292. doi: 10.2217/epi-2023-0026. Epub 2023 May 22.


This work examines differences in chromatin accessibility, methylation, and response to DNA hypomethylating agents between mismatch repair-deficient and non-mismatch repair-deficient endometrial cancer. Next-generation sequencing of a stage 1B, grade 2 endometrioid endometrial cancer tumor revealed microsatellite instability and a variant of unknown significance in POLE along with global and MLH1 hypermethylation. Inhibition of viability by decitabine in the study and comparison tumors was minimal, as shown by an inhibitory effect of 0 and 17.9, respectively. Conversely, the inhibitory effect of azacitidine on the study tumor was more pronounced, at 72.8 versus 41.2. In vitro, mismatch repair-deficient endometrial cancer with MLH1 hypermethylation respond better to DNA methyltransferase inhibition by azacytidine (DNA/RNA inhibition), than to decitabine (DNA-only inhibition). Additional large studies are needed to substantiate our findings.

Keywords: DNA methylation; azacitidine; decitabine; endometrial cancer; epigenomics; mismatch repair.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA Methylation
  • DNA Mismatch Repair
  • Decitabine / pharmacology
  • Decitabine / therapeutic use
  • Endometrial Neoplasms* / drug therapy
  • Endometrial Neoplasms* / genetics
  • Endometrial Neoplasms* / pathology
  • Epigenomics*
  • Female
  • Humans


  • Decitabine

Supplementary concepts

  • Turcot syndrome