evaluate the differences in the expression of these markers in patients <40 years old stratified according to the original, three-tiered Nottingham Prognostic Index. Methods: We retrospectively collected data about 116 women <40 years old treated for earlystage breast cancer between 2011-2015. The NPI was calculated and patients were stratified into the 3 prognostic groups. We used Kisquare test to compare pathological characteristics between NPI groups. Results: We observed 26.7% NPI good prognosis, 44% intermediate prog- nosis, 29.3% poor prognosis. We observed no difference between the 3 groups in terms of: HR+ (64% vs 80% vs 84.4%, p¼0.12) and HER2 over- expression (35.5%, 21.4%, 23.4%). There was significantly more patients with triple negative tumours (13% vs 16% vs 19.8%, p¼0.008), Ki67>20% (42% vs 64%, vs 84%, p¼0.01) and grade SBR II-III (84% vs 94% vs 96% p¼0.02) in poor NPI group. Patients of good NPI group had also signifi- cantly less nodal rupture (15% vs 29% vs 52%, p¼0.001). Mitotic index was higher in poor prognostic group (median 3 vs 9 vs 14, p¼0.03). Conclusions: Our study showed that some poor prognosis marker such as: triple negative tumours, high SBR grade and Ki67 and high mitotic index were more commonly seen in moderate and poor NPI groups. In contrast no difference was seen in HR and HER-2 overexpression. A modified NPI score adapted to young women could show a more accurate evaluation. PO76 A POSTPARTUM DIAGNOSIS INCREASES RISK FOR AND DETERMINES AN ALTERED PROFILE OF METASTASIS IN YOUNG WOMEN'S BREAST CANCER Virginia Borges 2 , Erica Goddard 1 , Solange Bassale 1 , Troy Schedin 2 , Jeremy Johnson 2 , Ethan Cabral 2 , Sonali Jindal 1 , Motomi Mori 1 , Traci Lyons 2 , Pepper Schedin 2 . 1 Oregon Health Science University, Cell, Development and Cancer Biology, Portland, Oregon, USA 2 University of Colorado Denver, Medical Oncology, Aurora, USA A diagnosis of breast cancer in a woman in the early years after a childbirth has been shown to increase risk for metastasis and death, however, limited data exists on how many years postpartum does this risk prevail, what known clinically prognostic factors are associated with this risk, and what are the pattern of metastasis in these women. This study was conducted to determine how many years after the most recent childbirth that a post- partum breast cancer diagnosis is associated with the increased develop- ment of distant metastatic disease. Also, to evaluate known clinical prognostic factors, including tumor proliferation status on influencing the increased risk for metastasis for postpartum breast cancer. This cohort study enrolled 802 cases as a sub study of the larger Colorado Young Women’s Breast Cancer Cohort (>9000 cases), with cases collected from 1991-2014. This is a multicenter study involving a tertiary care, academic hospital-based breast center and its regional affiliate. Included subjects are women diagnosed with stage I-III invasive breast cancer age 45 and under for whom parity data on timing of last childbirth was available, had un- dergone treatment with curative intent, and had known metastatic disease specific data. The studies primary objective is metastasis-free survival, based on first clinical documentation of metastasis by radiologic or physical exam findings, or date of pathologic confirmation. The primary exposure was prior childbirth or no prior childbirth and the time between the most recent childbirth and diagnosis of breast cancer. The results demonstrate that a diagnosis of breast cancer up to ten years postpartum increases the risk for metastasis. This increased risk is most associated with stage I/II diagnosis and is present in both ER+ and ER- cases. ER+ cases show a prolonged timeline of risk up to 15 years post diagnosis, high- lighting an under-recognized risk for young mothers with luminal cancer. Postpartum breast cancer is also associated with an increase in lymph node involvement and lymphovascular invasion, which aligns with the known mechanism of increased lymphangiogenesis in preclinical models. Lastly, increased liver metastasis occurs in postpartum breast cancer at time of first metastasis in comparison to nulliparous controls, highlighting the increased risk for mortality from a postpartum diagnosis. PR77 PROGNOSTIC VALUE OF BREAST CANCER SUBTYPES BASED ON ER/PR, HER2 EXPRESSION AND KI-67 INDEX IN WOMEN RECEIVED ADJUVANT THERAPY AFTER CONSERVATIVE SURGERY FOR EARLY STAGES BREAST CANCER A RETROSPECTIVE CLINICAL STUDY MennaAllah Fouda. Tanta University Hospital, Clinical Oncology and Nuclear Medicine Dpt., Tanta, Egypt Purpose: To evaluate the prognostic effect of breast cancer subtypes on local relapse rates, distant metastases, and survival in women underwent breast conservative surgery for early stages breast cancer. Patients and Methods: Data of 100 patients affected by early stage breast cancer and treated with breast-conserving therapy were reviewed. Based on the basis of receptor status and HER-2 status, patients were grouped as: luminal A (ER + and/or PR+, Ki67 low and HER2-), luminal B (ER + and/or PR+, Ki67 high and/or HER2+), HER2-positive (ER-, PR- and HER2+) and triple negative (ER-, PR, HER2-). Distribution of variables among subtypes was evaluated with Pearson’s test. Survival rates were calculated with life tables; Cox regression stepwise method was used to identify predictive variables of survival. Results: Range of age of the patients was 18-50 years old and median follow up time of 40 months (range 36.83-43.17). Breast cancer specific survival and distant metastases rates were different among breast cancer subtypes (both outcomes P¼ 0.001), there was significant difference regarding local relapse rates (P¼ 0.002 ). Axillary nodes status (P¼ 0.007), adjuvant therapy (P¼ <0.001) and breast cancer subtypes resulted prog- nostic factors of breast cancer specific survival; axillary node status (P¼ 0.007) and breast cancer subtypes had an impact on distant metastases. Conclusions: In our study, breast cancer subtype seems a prognostic factor of breast cancer specific survival and distant metastases rates & of local relapse rate. Patients could be submitted to conservative surgery, if feasible, but considering the differences in survivals, patients with worse prognosis should receive more aggressive adjuvant treatment PR78 DELVING KS-01 AS A NOVEL THERAPEUTIC STRATEGY IN TREATING BREAST CANCER Sourav Taru Saha, Mandeep Kaur. University of the Witwatersrand, School of Molecular and Cell Biology, Johannesburg, South Africa Cancer cells have an increased need for cholesterol, which is required for cell membrane integrity. Cholesterol accumulation has been described in various malignancies including breast cancer. Cholesterol has also been known to be the precursor of estrogen and vitamin D, both of which play a key role in the histology of breast cancer. Thus, depleting the cholesterol levels in cancer cells is a proposed innovative strategy to treat cancer. Therefore, novel cholesterol-depleting compounds are currently being investigated. KS-01 is a cyclic amylose oligomer composed of glucose units. It solubilizes the cholesterol and is proven to be toxicologically benign in humans. This led us to hypothesize that it might deplete cholesterol from cancer cells and may prove to be a clinically useful compound. Our work provides preliminary experimental evidences to support this hypothesis. We identified the potency of KS-01 in vitro against two breast cancer cell lines: MCF-7 (Estrogen positive, ER+), MDA-MB-231(Estrogen negative, ER-) and compared the results against a normal cell line: MRC-5 (Normal Human Lung Fibroblasts) using cytotoxic, apoptosis, protein expression and cholesterol based assays. KS-01 treatment reduced intracellular cholesterol resulting in significant breast cancer cell growth inhibition through apoptosis. The results hold true for both ER+ and ER-. These data suggest that KS-01 can prevent cholesterol accumulation in breast cancer cells and is a promising new anticancer agent. We are currently testing our hy- pothesis in vivo to validate our in vitro results. N.B: We have submitted the preliminary data to WITS ENTERPRISE (Uni- versity’s internal patenting agency); therefore the chemical name has been kept classified. Once we get our in vivo data, the compound would be patented for its mechanism of action in Breast cancer. Participants’ Abstracts / The Breast 41 (2018) S9eS32 S20