PP197 - EXPLORING MIRNA EXPRESSION PATTERN IN SKELETAL MUSCLES OF PATIENTS WITH A NEW DIAGNOSIS OF BREAST CANCER

PP197

EXPLORING MIRNA EXPRESSION PATTERN IN SKELETAL MUSCLES OF PATIENTS WITH A NEW DIAGNOSIS OF BREAST CANCER

S. Orlando¹, F. Tambaro^1,*, G. Imbimbo¹, C. Gallicchio¹, M. I. Amabile², M. Muscaritoli¹, A. Molfino^1,3

¹Department of Translational and Precision Medicine, ²Department of Surgical Sciences, ³Department of Interdisciplinary Studies on WellBeing, Health and Environmental Sustainability (BeSSA), Sapienza University of Rome, Rome, Italy

Rationale: Skeletal muscle (SM) changes are prognostic factors in women diagnosed with breast cancer (BC). SM wasting involves disruptions in metabolic pathways, increased apoptosis, and impaired regeneration, all closely linked to inflammation. Several studies have shown that microRNAs (miRNAs) are involved in SM homeostasis, but their specific roles in cancer-related SM alterations remain unclear. Our study aims to investigate the association between SM-derived miRNA expression and body composition parameters, including muscularity levels, in a cohort of newly diagnosed BC patients (BCP).

Methods: SM biopsies were collected from newly diagnosed BCP (n=24) and controls (C, n=6) at the time of surgery. Relative expression levels of miRNAs were assessed by RT-qPCR. BCP were stratified by fat-free mass index (FFMI, kg/m2), estimated by bioelectrical impedance analysis, into low (LMM) and high muscle mass (HMM) groups.

Results: In SM samples, we found an upregulation of miR-29a, -29b, -133a, and -206 in BCP compared to C (p<0.05). These miRNAs were upregulated according to BMI categories, particularly in BCP with BMI (kg/m²) ≥ 25 compared to C (p<0.05). Importantly, when stratifying BCP by FFMI, SM-derived miR-206 was significantly lower in BCP with LMM vs HMM (p<0.05), with additional differences observed when FFMI was considered in combination with BC molecular subtypes. Specifically, miR-206 was significantly downregulated in BCP with Luminal B (LUM-B) and LMM vs LUM-B patients with HMM (p<0.05). Moreover, relative expression levels of mir-206 were positively correlated with FFMI in BCP (p=0.031; r=0.440).

Conclusion: Our findings suggest an association between SM-derived miR-206 and SM alterations in newly diagnosed BCP. Further studies are needed to validate these findings and elucidate their functional role.

Disclosure of Interest: None declared