Abstract PS1-04-21: Correlations Between MOTS-c, Body Fat, and Muscle Strength in a Diverse Ethnic Cohort of Breast Cancer Survivors in Hawai'i

Abstract: Correlations Between MOTS-c, Body Fat, and Muscle Strength in a Diverse Ethnic Cohort of Breast Cancer Survivors in Hawai'i Background: Mitochondria Open Reading Frame within the Twelve S rRNA c (MOTS-c) is known to respond to exercise, influencing metabolic, cardiovascular, and muscular systems. However, the connection between MOTS-c and markers of health and fitness in Asian cancer survivors is underexplored. Our study aimed to examine the impact of a 12-week concurrent exercise program on MOTS-c levels in Asian breast cancer survivors and determine if anthropometric and fitness-related factors correlate with pre- and post-exercise MOTS-c levels. Methods: Twenty-five breast cancer survivors participated in a 12-week concurrent exercise program. Metrics were assessed before and after the exercise program, including visceral/subcutaneous fat mass, volume, bone mass density (BMD), bone mineral content (BMC), body fat percentage, 1-repetition maximum (1-RM) strength, isokinetic peak torque and maximum work, as well as cardiorespiratory (VO2 peak) and muscular endurance. Plasma MOTS-c was measured using an in-house enzyme-linked immunosorbent assay. Statistical analyses, including t-tests and correlation analyses, were conducted. Results: There was a significant 8.3±13.0% increase in MOTS-c levels following exercise (pre: 254.6±39.9 pg/ml, post: 272.5±36.0 pg/ml, p=0.015). Based on varying responses, the participants were divided into two groups: low responders (n=11) and high responders (n=14). Eight low responders showed a decrease in MOTS-c after exercise, while high responders showed an 18% increase. Pre-exercise MOTS-c levels were positively correlated with baseline body mass, body fat percentage, muscular strength, isokinetic maximum work/torque, and changes in BMD and BMC (p<0.05) but not VO2 peak (p>0.05). When analyzed separately for low and high responders, these significant correlations were only present in the high responder group. Additionally, MOTS-c showed a weak negative correlation with muscular endurance as measured by the chair squat test, but for the high responders, a significant negative relationship was found between MOTS-c and core endurance, assessed by plank hold performance (p=0.0145). Summary: Our study showed significant improvement in MOTS-c levels following our exercise program, with high responders showing significant correlations between MOTS-c and body fat, skeletal muscular strength, and BMD and BMC. This exemplified that MOTS-c is associated with bone and metabolic health. Since MOTS-c is correlated with strength but not endurance, strength training should be emphasized in exercise programs aimed at improving cancer survivorship outcomes. Citation Format: J. Fukui, L. Imai, C. Shen, K. Baron, M. Toyama, I. Pagano, A. Oamil, H. Kumagai, J. Wan, P. Cohen, P. Yamada, C. Teranishi-Hashimoto. Correlations Between MOTS-c, Body Fat, and Muscle Strength in a Diverse Ethnic Cohort of Breast Cancer Survivors in Hawai'i [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS1-04-21.