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 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 (p0.05) but not VO2 peak (p0.05). 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.