Common European Mitochondrial Haplogroups in the Risk for Radiation-induced Subcutaneous Fibrosis in Breast Cancer...

Area of Science:

• Genetics
• Oncology
• Radiotherapy

Background:

• Mitochondrial DNA (mtDNA) variations' role in clinical radiosensitivity remains largely unexplored.
• Understanding factors influencing radiation-induced side effects is crucial for optimizing cancer treatment.

Purpose of the Study:

• To investigate the association between mitochondrial DNA (mtDNA) haplogroups and the risk of radiation-induced subcutaneous fibrosis.
• To evaluate the potential protective effect of specific mtDNA haplogroups in breast cancer patients undergoing radiotherapy.

Main Methods:

• Assessed subcutaneous fibrosis using the Late Effects of Normal Tissue-Subjective Objective Management Analytical (LENT-SOMA) scale in 286 Italian breast cancer patients.
• Determined eight mtDNA single nucleotide polymorphisms defining European haplogroups via polymerase chain reaction restriction fragment length polymorphism analysis.

Main Results:

• Kaplan-Meier analysis indicated that carriers of haplogroup H had a lower risk of grade ≥2 subcutaneous fibrosis (P=0.018).
• Multivariate analysis suggested haplogroup H as a protective factor (HR: 0.50, P=0.027), though not statistically significant after correction for multiple testing.

Conclusions:

• Mitochondrial haplogroup H shows a potential protective effect against radiation-induced fibrosis in breast cancer patients.
• These findings are preliminary and require validation in larger prospective studies due to the loss of significance after multiple testing correction.