Abstract PS17-38: Comprehensive association analysis of 21-gene recurrence score and overweight in breast cancer patients

Abstract

Abstract Background: The association between 21-gene recurrence score (RS) and host factors such as overweight remains unclear for breast cancer patients. The objectives of the current study are to comprehensively analyze the distribution, single gene expression, and prognostic predictive value of RS between overweight or non-overweight patients.Patients and methods: Luminal-like patients receiving surgery between January 2009 and December 2018 in the Comprehensive Breast Health Center, Shanghai Ruijin Hospital, with 21-gene RS results were retrospectively retrieved. Association and subgroup analysis between BMI and 21-gene RS were conducted. Single-gene expression in 21-gene RS panel was compared between overweight and non-overweight groups. Recurrence-free survival (RFS) and overall survival (OS) were calculated according to RS category and BMI status.Results: Among 1876 patients included, 442 (23.56%), 995 (53.04%) and 439 (23.40%) were classified into low, intermediate and high risk groups. RS category was significantly differently distributed between overweight and non-overweight patients (P=0.035). Overweight patients had a trend of lower RS score than patients with normal weight (25.13 vs 26.17, P=0.080). The effect of BMI on RS significantly varied according to age (P=0.012) and menstruation status (P<0.001). Compared to non-overweight patients, overweight ones presented with higher ER (P<0.001), PR (P<0.001), CEGP1 (P=0.017), Ki67 (P=0.020) and STMY3 (P=0.026) mRNA expression levels. Regarding menstrual status, postmenopausal women with BMI≥24 kg/m2 were associated with higher ER group score (P<0.001), with higher ER (P=0.041), PR (P<0.001), CEGP1 (P=0.005), as well as GRB7 (P=0.015) expression, which was not significant in premenopausal women. After a median follow-up of 39.40 months (range 1.67-119.53), overweight patients had similar RFS (P=0.670) and OS (P=0.077) to non-overweight ones. Moreover, RS category could significantly predict RFS in the whole population (P<0.001), in either those overweight (P=0.003) or non-overweight (P=0.019).Conclusion: 21-gene RS was differently distributed between overweight and non-overweight patients, which interacted with age and menopausal status. ER, PR, CEGP1, Ki67 and STMY3 genes were more expressed in overweight patients. RS category could predict RFS regardless of BMI status, which warranted further validation. Citation Format: Yiwei Tong, Weiqi Gao, Jiayi Wu, Siji Zhu, Ou Huang, Jianrong He, Li Zhu, Weiguo Chen, Yafen Li, Kunwei Shen, Xiaosong Chen. Comprehensive association analysis of 21-gene recurrence score and overweight in breast cancer patients [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS17-38.