Conclusions: This is the real-life description of clinical outcomes, for patients receiving eribulin therapy for MBC throughout the Russian Federation. Our experience with eribulin in MBC patients demon- strates it activity and safety in early lines of treatment and intensively pretreated patients. Conflict of Interest: No significant relationships. P143 Survival outcome of pregnancy associated breast cancer in resource limited country: an analysis A. Gogia 1 *, V. Raina 2 , S. Deo 1 , D. Sharma 1 , S. Mathur 1 . 1 AIIMS (All India Institute of Medical Sciences), New Delhi, India, 2 FMRI, Gurgaon, India Goals: Pregnancy-associated breast cancer (PABC) has been defined as breast cancer diagnosed during pregnancy or within 1 year of delivery. The primary objective of this study was to evaluate the clinicopathological characteristics and treatment outcome of patients with PABC Methods: Clinicopathological data of patients treated for PABC between 2001 and 2017 at All India Institute of Medical Sciences (AIIMS), New Delhi, India, were retrospectively reviewed. Results: Forty one patients with PABC were included in this study. The median age was 26.5 years (range 20–35). The median duration of symptoms was 10.5 months. The American Joint Committee on Cancer (AJCC)-7th edition, the stage distribution was, Stage I – 1, Stage II – 5, Stage III – 23 and in Stage IV -12 patients. Median clinical tumour size was 5.6 cm. Six patients were presented with the inflammatory breast cancer. Thirty patients were diagnosed after delivery, two patients in the first trimester, five patients in the second trimesterand four patients in the third trimester. Estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2/neu) positivity was 50%, 46%and 38%, respectively. Only 5 patients have received targeted therapy due to financial constraints. Triple negative status was found in 22% of cases. Sixty % of patients had a high-grade tumor and 70% had pathological node positivity. With a median follow-up of 42 months, 3 years relapse free survival and overall survival was 40% and 50% respectively. Bone was the most common site for systemic relapse. In 35 patients (85%), there was a diagnostic delay between occurrence of the presenting symptoms and the initiation of breast mass workup because of lactation and negligence Conclusions: PABC mostly presents with advanced-stage disease with bad biology (half of them were ER/PR negative, 38% was HER2/ neu positive and nearly two third are high grade) resulted poor outcome. There can be a substantial diagnostic delay before these patients receive medical attention. Pre and post partum breast examination should be included at primary health care system during peripartum period for early diagnosis and good treatment outcome Conflict of Interest: No significant relationships. P144 Retrospective review of Her2 positive metastatic breast cancer patients who received Pertuzumab and Herceptin as a first line therapy at KFSH&RC (single institute experience) from 2013 to 2016 K. Suleman 1,2 , A. Mushtaq 2 *, E. Haque 2 , A. Badran 1,3 , D. Ajarim 1 , T. Tweigeri 1 , A. Elashwah 1,4 , A. Shahin 1,5 , K. Khan 1 , A. Alsayed 1 . 1 Oncology, King Faisal Hospital and Research Center, Riyadh, Saudi Arabia, 2 Al Faisal University, Riyadh, Saudi Arabia, 3 Ain Shams University, Cairo, Egypt, 4 Center of Clinical Oncology and Nuclear Medicine, Kasr Aleini, Cairo, Egypt, 5 National Cancer Institute, Cairo University, Cairo, Egypt Goals: This retrospective study will evaluate response rate, progres- sion free survival (PFS), and overall survival (OS) for Her2 positive metastatic breast cancer (MBC) patients treated with Trastuzumab, Pertuzumab/Docetaxel as a first line therapy in King Faisal Specialist Hospital & Research Center, Riyadh, SA. Methods: 75 patients were retrospectively identified and had been diagnosed with Her2 positive MBC between the years of 2013 to 2016. All patients had baseline full lab work (including CBC; LFT; and CA15.3) and imaging (including US breast; mammography; CTchest, abdomen, and pelvis; bone scan; and ECHO). 41 patients (54.7%) had ER +ve disease while 34 (45.3%) had ER −ve disease. 44 patients (59%) had visceral metastasis, 8 (10%) had bone metastasis, and 23 (31%) had both types of metastasis. Treatment was continued until disease progression or development of severe intolerable toxicity. All patients had regular follow-up every 3 months (including history and physical examination with repeated imaging tests to assess response). Results: 13 patients (17.3%) had complete response (CR); 41 (54.7%) showed partial response (PR); 8 (10.7%) had a stable disease (SD); and 9 (12%) showed progression of disease (PD). 2 patients stopped (one due to allergy to treatment and the other due to drop in EF). There was no grade 3–4 toxicity; 15 patients had low grade febrile neutropenia. 5-year progression free survival was 21% with a median of 36 months. The 5-year OS ratewas 87%, with median OS not yet reached. ER +ve and ER −ve patients had no statistically significant difference in OS, although ER −ve patients showed a better trend in OS. Conclusions: Trastuzumab, Pertuzumab/Docetaxel as a first line therapy in Her2 positive MBC is a highly effective regimen in our patient cohort with 5 years PFS of 21% and OS rate of 87%. It also had a tolerable toxicity profile. Conflict of Interest: No significant relationships. P145 The relationship between lymphocyte cytosolic protein 1 expression and endocrine therapy drug resistance in elderly patients with hormone receptor-positive breast cancer Z.G. Du 1 *, Q. Lv 2 . 1 Breast Cancer Surgery, West China Hospital of Sichuan University, Chengdu, China, 2 Breast Surgery, West China Hospital of Sichuan University, Chengdu, China Goals: Endocrine therapy has an essential role in the systemic treatment of elderly patients with hormone receptor-positive breast cancer. Therefore, endocrine therapy resistance severely affects the survival of elderly patients. This study aims to investigate the critical genes and mechanisms of primary drug resistance in endocrine therapy of breast cancer. Methods: This study included 54 samples of patients with breast cancer who were ≥65 years old, with estrogen receptor (ER) positive or progesterone receptor (PR) positive from GSE25066 and GSE45255, and MCF-7 breast cancer cell lines with primary endocrine therapy sensitive (n = 8) as well as drug resistance (n = 10) from GSE67916. Weighted gene co-expression network analysis (WGCNA) combined with differential gene analysis were used to systematically study genes associated with breast cancer endocrine therapy resistance and distant recurrence. Results: Differential gene analysis revealed that 379 differentially expressed genes in endocrine-sensitive and -resistant MCF-7 cells. The WGCNA analysis method constructed 13 co-expressed gene modules. Among them, yellow module showed a significantly positive correlation ( p = 0.04, correlation = 0.29) with distant metas- tasis-free survival (DMFS) event and a negative correlation ( p = 0.1, correlation = -0.21) with DMFS time. WGCNA also identified six critical genes highly associated with distant metastasis in the yellow module. However, only three critical genes were found to be correlated with both drug resistance and survival. It is strange that the cancer cells were more sensitive to endocrine therapy but patients will have a poor prognosis when S100 Calcium Binding Protein A4 (S100A4) was highly expressed. However, high expres- sions of tissue inhibitor of metalloproteinases 2 (TIMP2) and especially lymphocyte cytosolic protein 1 (LCP1) showed endocrine therapy resistance as well as decreased distant relapse-free time. Further analysis revealed decreased expression of LCP1 and no endocrine therapy resistance of tumor cells after blocking androgen effects in the endocrine-resistant MCF-7 cells. Poster Abstracts I / The Breast 44S1 (2019) S15–S78 S64