Can synthetic lethality approach be used with DNA repair genes for primary and secondary MDS?

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Cancer-specific DNA repair defects enable synthetic lethality approaches.
• Gene expression and mutation analysis (GEMA) previously identified insufficient BRCA or non-homologous end joining (NHEJ) expression for predicting PARP inhibitor response.

Purpose of the Study:

• To evaluate the role of DNA repair pathways in myelodysplastic syndrome (MDS) by analyzing gene expression.
• To explore the potential of synthetic lethality strategies in MDS treatment.

Main Methods:

• Gene expression analysis of single-strand break repair genes (XPA, XPC, XPG/ERCC5, CSA/ERCC8, CSB/ERCC6) and double-strand break repair genes (ATM, BRCA1, BRCA2, RAD51, XRCC5, XRCC6, LIG4) in 92 MDS patients (73 de novo, 9 therapy-related).
• Comparison of gene expression in MDS subtypes and normal controls.
• Evaluation of gene expression patterns in the GEPIA Database across 30 cancer types.

Main Results:

• Therapy-related MDS (t-MDS) showed significant downregulation of the BRCA1-BRCA2-RAD51 axis compared to normal controls.
• XRCC6 expression was significantly lower in de novo MDS patients, especially those with chromosomal abnormalities.
• LIG4 downregulation correlated with poor prognostic markers in de novo MDS, including low hemoglobin, low neutrophils, excess blasts, high IPSS-R scores, and AML transformation.
• A similar downregulation pattern was observed in primary and secondary MDS in the GEPIA database.

Conclusions:

• Altered DNA repair gene expression in MDS suggests synthetic lethality is a viable therapeutic strategy.
• Targeting DNA repair pathways beyond BRCA1/2 status may benefit MDS patients.
• Clinical trials investigating PARP1 inhibitors for MDS are warranted.