@conference{
author = "Petrović, Nina and Srbljak Ćuk, I. and Marjanovć Đorić, D. and Petrović, I. and Paunović, P. and Medić Milijić, Nataša",
year = "2023",
abstract = "Introduction Nearly 60% of patients with breast cancer (BC) undergo radiotherapy (RT). A significant proportion of patients experience side effects that can influence their quality of life and treatment effectiveness. Gene and microRNA expression patterns may be associated with individual patients' sensitivity to RT. Material and Methods Expression levels of miR-133b, miR-206, and their target genes matrix metalloproteinase 9 (MMP9) and vascular endothelial growth factor (VEGFA) were investigated in normal tissue adjacent to tumors of 27 BC patients. Sixteen out of 27 (59.3%) patients underwent RT, while 13 of them had breast skin reactions (acute dermatitis). Patients with acute dermatitis were divided into two groups, H-hypofractionated and F-standardly fractionated group. The H group underwent 16 fractions of RT (2.65 Gy), while the second group-F had 25 fractions (2 Gy) or 25 fractions plus boost. All patients from the F group had acute dermatitis before the 25th fraction, so the boost did not influence the time of toxicity occurrence. After the RNA extraction, followed by reverse transcription, expression levels of the four molecules were measured by RT-qPCR. Relative quantity (RQ) units were calculated by a comparative 2-ddCt method. Results and Discussions MiR-133b/206 and MMP9/VEGFA gene levels did not differ between patients from H and F groups (p = 0.573; p = 0.143; p = 0.727; p = 0.582, respectively). The F group was divided into two subgroups-earlier (E) subgroup with patients with skin reactions before or at 20th fraction, and the later (L) subgroup with patients with skin reactions after 20th fraction. VEGFA gene expression was significantly higher in the E group compared with the L group, indicating that it may be a specific predictor of earlier onset of acute skin reaction in the normal breast tissue of patients undergoing RT (p = 0.036, Mann–Whitney U test). MicroRNAs miR-133b, miR-206, and MMP9 were not associated with earlier or later onset of skin reactions in this cohort (p = 0.343; p = 0.800; p = 0.786). It has been also shown that some VEGFA polymorphic regions can predict normal tissue reaction to RT in BC patients. Conclusion Higher levels of VEGFA are associated with earlier onset of skin reactions, but in patients undergoing conventionally fractionated RT. VEGFA expression difference indicates that neoangiogenesis capacity might be associated with individual risk of earlier occurrence of acute side effects following RT.",
publisher = "EACR - European Association for Cancer Research",
journal = "EACR 2023 Congress : Annual Congress of the European Association for Cancer Research : Abstracts",
title = "Higher VEGFA expression levels are associated with earlier onset of acute breast skin reactions of BC patients treated with radiotherapy",
pages = "P-0422-P-0422",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12237"
}
