PS6K1 as an efficacy marker of GnRH agonist with premenopausal breast cancer. Issue 7 (July 2019)

• Record Type: Journal Article
• Authors: Park, Chan Sub; Choi, Jihye; Seong, Min-Ki; Hong, Sung-Eun; Kim, Jae-Sung; Park, In-Chul; Seol, Hyesil; Noh, Woo Chul; Kim, Hyun-Ah
• Is Part Of: Endocrine connections. Volume 8:Issue 7(2019)
• Page Start: 863
• Page End: 869
• Publication Date: 2019-07
• Subjects: breast cancer -- treatment efficacy -- ribosomal protein S6 kinase 1 -- GnRH agonist; Endocrinology -- Periodicals; 616.4005
• DOI: 10.1530/EC-19-0101
• Languages: English
• ISSNs: 2049-3614

Abstract

Abstract : Estradiol is a key factor for tumorigenesis and prognosis of hormone receptor-positive breast cancer. Adipocytes are one source of estradiol in patients with breast cancer. Recent studies have shown that phosphorylated ribosomal protein S6 kinase-1 plays a critical role in adipogenesis. Therefore, estrogen depletion therapy might have beneficial effects in phosphorylated ribosomal protein S6 kinase-1-positive breast cancer. This study was conducted to evaluate the value of phosphorylated ribosomal protein S6 kinase-1 as a marker for gonadotropin-releasing hormone agonist treatment, a form of estrogen depletion therapy, for premenopausal patients with HR-positive, human epidermal growth factor receptor 2-negative breast cancer. We reviewed the medical records of 296 premenopausal patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative primary invasive breast cancer treated between 2008 and 2015. Phosphorylated ribosomal protein S6 kinase-1 positivity was defined by immunohistochemical staining scores of 1+, 2+ and 3+, whereas a score of 0 was considered negative. Phosphorylated ribosomal protein S6 kinase-1-positive tumors were found in 74.0% of the patients. In the phosphorylated ribosomal protein S6 kinase-1-positive group, disease-free survival of patients treated with a gonadotropin-releasing hormone agonist was significantly longer than that of patients treated without a gonadotropin-releasing hormone agonist (mean 106.7 months vs mean 91.1 months, P = 0.018). Phosphorylated ribosomal protein S6 kinase-1 is a potential biomarker for predicting the efficacy of gonadotropin-releasing hormone agonist therapy in premenopausal patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer.