Abstract 1002: An association between Annexin A1 (ANXA1) and loss of progesterone receptor expression in estrogen receptor-positive breast cancer

Abstract

Abstract Purpose: There is a strong body of evidence that low expression of progesterone receptor has a negative prognostic value in estrogen receptor (ER)-positive breast cancer. To discover key factors associated with PR-loss in ER-positive cancer, we conducted cell line experiments and investigated clinical samples. Methods: We generated PR knock-down MCF7 and T47D cell lines using lentiviral transfection with PR shRNA. Gene expression microarray analyses were performed using Illumina Chip. Annexin A1 (ANXA1) was evaluated for tissue microarray (TMA) using HER2-negative human breast carcinoma. Results: When PR-intact and PR-knockdown cells were compared using gene-expression profiles, ANXA1 was commonly identified as a molecule associated PR-knockdown in both MCF7 and T47D cell lines. Further, the mRNA expression of ANXA1 was elevated by PR-knockdown in both cell lines. In HER2-negative patients (n=370), ANXA1-positive tumors were associated with a lack of PR expression (P<0.001). The patients with ANXA1-positivity had a poor survival outcome in terms of overall survival and metastasis-free survival. Conclusions: Our findings inform that ANXA1 may act a role in tumor progression of PR-lacking breast cancer. Citation Format: Sung Gwe Ahn, Soong June Bae, Chihwan Cha, Chang Ik Yoon, So Eun Park, Joon Jeong. An association between Annexin A1 (ANXA1) and loss of progesterone receptor expression in estrogen receptor-positive breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1002.