M. Hikichi

Differences in subtype distribution between screen-detected and symptomatic invasive breast cancer and their impact on survival

PurposeStage shift is considered a major reason for more favorable outcomes in patients with screen-detected breast cancer. However, even after adjusting for clinical stage, unresolved issues concerning the reasons for a survival benefit associated with screening programs remain. This study aims to evaluate differences in subtype distribution and outcomes among patients with screen-detected and symptomatic invasive breast cancer and assess whether variations in subtype distribution could explain differences in prognosis.MethodsSurvival analysis was performed to estimate the likelihood of distant recurrence and death in 1132 patients. Subtypes were defined as luminal A [estrogen receptor (ER)+ and/or progesterone receptor (PR)+, human epidermal growth factor receptor 2 (HER2)−, and Ki67 low], luminal B (HER2−) (ER+ and/or PR+, HER2−, and Ki67 high), luminal B (HER2+) (ER+ and/or PR+ and HER2+), HER2 overexpressing (ER−, PR−, and HER2+), and triple negative (ER−, PR−, and HER2−).ResultsScreen-detected cancers had favorable clinicopathological characteristics, such as smaller tumor size and a lower frequency of lymph node involvement. Women with screen-detected cancers had a survival advantage. Subtype distribution differed significantly among women with screen-detected and symptomatic cancer. Screen-detected cancers were more likely to be luminal A and less likely to be HER2 overexpressing or triple negative cancer compared with symptomatic cancers (luminal A 61.3 vs. 44.2%, HER2 overexpressing 4.0 vs. 8.0%, triple negative 8.0 vs. 15.9%). Node status, mode of detection, and subtype were independent prognostic factors in the multivariate analysis.ConclusionsDifferences in subtype distribution between screen-detected and symptomatic cancer could partially explain differences in outcomes.

Estradiol suppresses phosphorylation of ERα serine 167 through upregulation of PP2A in breast cancer cells

Aromatase inhibitors (AIs) are effective endocrine therapeutics for postmenopausal women with estrogen receptor (ER)α-positive breast cancer. However, the efficacy of the treatment is often limited by the onset of AI resistance, owing to the phosphorylation of ERα serine 167 (Ser167). Previous studies have indicated that hyperactivation of the phosphoinositide-3 kinase/RAC serine/threonine-protein kinase signaling pathway occurs in AI-resistant breast cancer models, which coincides with elevated levels of ERα phosphorylation at Ser167. The tumor suppressor serine/threonine-protein phosphatase 2A (PP2A) regulates the phosphatidylinositol 3-kinase/RAC serine/threonine-protein kinase signaling pathway. A previous study indicated that PP2A inhibition decreased ERα Ser167 phosphorylation and estradiol (E2)-independent cell growth. The present study investigated the potential relevance of PP2A in E2 deprivation-resistant MCF-7 cells. E2 depletion reduced the susceptibility of MCF-7 cells to inhibitors of mechanistic target of rapamycin (mTOR) and significantly increased ERα Ser167 phosphorylation and decreased expression of PP2A. Conversely, long-term E2-deprived (LTED) MCF-7 cells, a model of AI-resistant breast cancer, exhibited decreased ERα Ser167 phosphorylation and further upregulation of PP2A in E2-containing medium. The PP2A activator forskolin (FSK) significantly inhibited LTED cell proliferation by increasing the effect of everolimus (Eve), an mTOR inhibitor. In summary, the present study provides further evidence that PP2A represents a therapeutic target for AI-resistant breast cancer.

Forskolin increases the effect of everolimus on aromatase inhibitor-resistant breast cancer cells

Aromatase inhibitor (AI) resistance is a major obstacle in the treatment of estrogen receptor-positive breast cancer. Everolimus (EVE) ameliorates AI-resistant breast cancer and is therefore used in cancer treatment. However, some patients show resistance to EVE. Here, we used 30 clones of long-term estrogen-deprived (LTED) MCF-7 cells as a model of AI-resistant breast cancer. We examined changes in protein phosphatase type 2A (PP2A) and cancerous inhibitor of PP2A (CIP2A), a negative regulator of PP2A, in LTED cells treated with EVE. In LTED cells with high sensitivity to EVE, CIP2A expression decreased at low EVE concentrations; however, in LTED cells poorly sensitive to EVE, CIP2A and PP2A did not change upon exposure to EVE. Therefore, we hypothesized that there is a relation between expression of CIP2A and sensitivity to EVE. Knockdown of CIP2A increased the sensitivity to EVE in three clones poorly sensitive to EVE. Additionally, we found that treatment with FSK, which activates PP2A, increased the sensitivity of the cells to EVE. Our data point to CIP2A and PP2A as novel therapeutic targets for AI-resistant breast cancer.

A Hypoglycemia-inducing Giant Borderline Phyllodes Tumor Secreting High-molecular-weight Insulin-Like Growth Factor II: A Case Report with Immunohistochemistry and a Western Blot Analysis

A 50-year-old woman with a large right breast mass was emergently hospitalized for generalized weakness and fatigue. A histological examination of tumor biopsy specimens revealed a phyllodes tumor (PT). She suddenly lost consciousness due to severe hypoglycemia. Non-islet cell tumor hypoglycemia (NICTH) due to the PT was suspected. The tumor was emergently resected. A histological examination revealed a borderline PT. The patient recovered from the hypoglycemic episode. High-molecular-weight insulin-like growth factor II was detected in serum that had been collected preoperatively and in the tumor tissue, but not in serum that had been collected postoperatively. We herein present a case of a borderline PT with NICTH.

Abstract P5-15-10: Eribulin mesylate (eribulin) showed inhibitory effects on epithelial-mesenchymal transition (EMT) in tumors of metastatic breast cancer patients. -First preliminary report of a prospective study-

Background: EMT is thought to contribute to metastasis in patients with breast cancer, leading to their poor prognosis. Pivotal phase III trials have demonstrated that eribulin improved overall survival in patients with triple negative metastatic breast cancer (MBC). Preclinical studies have shown that eribulin suppressed EMT and this phenomenon could be one of reason for an improved prognosis of MBC patients treated with eribulin. However, there is no direct clinical data on the effect of eribulin treatment on EMT in tumors of MBC patients. We designed a prospective study to clarify if eribulin treatment suppresses EMT in tumors of MBC patients. Patients and methods: Patients with recurrent or MBC were treated with eribulin (1.4 mg/m2 intravenously on days 1 and 8 of a 21-day cycle). Dose reductions were allowed according to eribulin9s prescribing information. Treatment continued until disease progress, unacceptable toxic effects, or discontinuation requests from patients or physicians. Breast cancer tissue samples were obtained from all patients before and on day 15±4 of 1st cycle of eribulin treatment. The quantitative analysis of mRNA levels of EMT markers (E-cadherin, cytokelatin18, cytokelatin19, N-cadherin, vimentin, ZEB1, Slug, Snail, and Twist) were carried out by qPCR. Primary outcome measure was to assess the change from baseline to day 15±4 in mRNA levels of EMT related markers in tumor tissue. This study was approved by the Ethic Committee of Fujita Health University. Results: Eleven patients were enrolled. Median age of the patients was 63 years old (44-72). Of the 11 tumors, 6 were luminal B and 5 were triple negative (TN). Median number of prior chemotherapy regimen for recurrent or metastatic disease was 0 (0-3). Four patients were treated with dose reduced eribulin (1.1 mg/m2) and administration of eribulin on day 8 during 1st cycle of the treatment were skipped in 2 patients. To identify meaningful EMT markers, differences in expression levels of each EMT marker were investigated between TN and luminal B tumors. At baseline mRNA levels of N-cadherin and vimentin were higher in TN tumors than in luminal B tumors, 8.12±10.78 vs 1.02±0.68, 5.13±4.50 vs 0.88±0.47, respectively. After the treatment, a decrease of expression of N-cadherin and vimentin was more frequent in TN tumors (100% and 80%, respectively) than in luminal B tumors (33.3% and 16.7%, respectively). Frequency of a decrease of expression of ZEB1, Slug, Snail, and Twist in TN tumors and luminal B tumors were 80% (TN) vs 83.3% (luminal B), 80% vs 16.7%, 40% vs 66.7%, and 100% vs 50%, respectively. Conclusions: This is the first prospective study to investigate the effect of eribulin treatment on expression of EMT markers in tumors of MBC patients. We demonstrated that eribulin treatment suppressed EMT in tumors. Our results suggested that eribulin showed antitumor effect by improving the tumor microenvironment. In our study, eribulin seems to have different effects on EMT pathway in individual cases. Our findings may provide a light to a scientific basis for solving underlying mechanisms for improvement of overall survival of patients with MBC treated with eribulin. Citation Format: Utsumi T, Hayashi T, Kobayashi N, Hikichi M, Ushimado K, Ri Y, Nakano S, Fujii K, Ando T. Eribulin mesylate (eribulin) showed inhibitory effects on epithelial-mesenchymal transition (EMT) in tumors of metastatic breast cancer patients. -First preliminary report of a prospective study- [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-15-10.

276PBIOLOGICAL AND CLINICAL IMPLICATIONS OF AROMATASE INHIBITORS FOR NEOADJUVANT THERAPY IN BREAST CANCER

ABSTRACT Aim: Neoadjuvant aromatase inhibitors (AIs) therapy has become acceptable. Estrogens play a major role in promoting the growth of breast cancers (BCs). Androst-5-ene-3b,17b-diol (ADIOL) possesses estrogenic properties. Here we report the efficacy of AIs and the influence of letrozole (LET) on BC tissue and plasma levels of estrone (E1), estradiol (E2), estrone sulfate (E1S), ADIOL, and androstendione (AONE) in postmenopausal women undergoing neoadjuvant therapy for estrogen receptor (ER)–positive BCs. Methods: Twenty-nine postmenopausal patients with stage I (n = 3), IIA (n = 11), IIB (n = 5), IIIA (n = 2) and IIIB (n = 9) BCs were treated with anastrozole, LET or exemestane as neoadjuvant treatment. One patient had bilateral BC. Plasma and BC tissue samples were obtained from 9 patients before and after 4 months of neoadjuvant therapy with LET. Steroids concentrations were measured by liquid chromatography/ electrospray tandem mass spectrometry. Results: One of 30 tumors showed complete response (CR), 15 showed partial response (PR) and 14 showed stable disease (SD). All treatments were well tolerated. After treatment, a decrease of progesterone receptor expression was more frequent in responding tumors (93.8%) than in non-responding tumors (35.7%). Suppression of Ki67 after treatment was significantly greater in responding tumors than in non-responding tumors (P = 0.002). The mean BC tissue levels of E1, E2, E1S, ADIOL, and AONE at base line were 0.534, 0.409, 0.13, 1.65, and 6.09 pmol/g, respectively. After neoadjuvant therapy, the levels of E1, E2, E1S, ADIOL, and AONE were 0.002, 0008, 0.002, 2.22, and 5.63 pmol/g, respectively. The mean plasma levels of E1, E2, E1S, ADIOL, and AONE at base line were 621.5, 27.0, 1799.5, 1033, and 2258 pmol/l, respectively. After therapy, the levels of E1, E2, E1S, ADIOL, and AONE were 1.7, 1.6, 3.4, 1111, and 2826 pmol/l, respectively. LET significantly suppressed estrogens. Although plasma and tissue ADIOL levels were high after treatment, there was no progress disease in the 9 cases. With a median follow up of 69 months, there was no significant difference in overall survival between patients with CR or PR and those with SD. Conclusions: Neoadjuvant AIs therapy provided satisfactory efficacy and safety profiles. The activity of AIs was correlated with significantly reduced estrogens levels, but not with ADIOL levels. Disclosure: All authors have declared no conflicts of interest.

Abstract P3-02-05: Subtypes of screen-detected invasive breast cancer and symptomatic invasive breast cancer and their impact on survival

Background: Breast cancer is a worldwide problem which urgently requires solution, in many countries still being the most common cause of malignancy associated death. The screening program aims to detect early breast cancer to improve survival. We investigated the clinicopathrogical characteristic including intrinsic subtypes and outcome of patients with screen-detected invasive breast cancer (S-DIBC) compared with those with symptomatic invasive breast cancer (SIBC). Material and Methods: From January 2005 to December 2011 840 patients with invasive breast cancer who underwent surgery at our hospital were included. There were 195 S-DIBCs and 645 SIBCs. We retrospectively reviewed the clinical and pathologic data. Ki-67 LI was categorized as low ( or = 15%). Tumors were classified into four groups based on the expression of ER, PgR, Ki-67 and HER2 as follows: luminal A (ER+ and/or PR+, and HER2− and Ki67 low), luminal B (ER+ and/or PR+, and HER2+ or Ki67 high), HER2 disease (ER−, PR−, HER2+), and triple negative (ER−, PR−, HER2−). Overall survival (OS) and relapse-free survival (RFS) curves were generated using the Kaplan- Meier method. Survival comparisons were made with the log-rank test, the level of significance was taken to be 0.05. SPSS 18.0 software package was used for statistical analysis. Results: S-DIBC was associated with smaller tumor size, less lymph node involvement, and earlier stage compared with SIBC (P Conclusions: Our results suggest that subtype distribution of S-DIBC differs from that of SIBC. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-02-05.

Abstract P5-14-01: The Influence on Upper Limb Function after Sentinel Lymph Node Biopsy or Axillary Lymph Node Dissection

Background Sentinel lymph node biopsy (SLNB) is accepted as a method in patients with clinically negative axillary lymph nodes because it was assumed to be associated with improvement of upper limb morbidity. The purpose of this study was to investigate that SLNB reduces upper limb morbidity of patients with breast cancer compared with axillary lymph node dissection (ALND). Methods The study comprised 362 patients with breast cancer who underwent measuring the upper limb mobility before and after surgery (at discharge, 1 month and 3 months after surgery). 241 patients underwent SLNB, 121 patients underwent ALND. In the SLNB group, 148 patients (48.1%) underwent breast conserving surgery (BCS), 67 patients (18.5%) underwent mastectomy. In the ALND group, 68 patients (18.8%) underwent BCS, 53 patients (14.6%) underwent mastectomy. Upper limb mobility was measured by the difference of the angle of the flexion and the angle of abduction between before and after surgery. The recovery defined that the difference of the angle between before and after surgery, is within 10 degree. The recovery rate was investigated by Kaplan-Meier method, and comparisons were evaluated using the log-rank test. Results The recovery rate of patients in the SLNB group was 85% in measuring flexion, 90% in measuring abduction 3 month after surgery. The recovery rate of patients in the ALND group was 52% in measuring flexion, 58% in measuring abduction. The recovery rate of upper limb function increase by SLNB than by ALND (P Conclusions SLNB reduces upper limb morbidity of patients with breast cancer compared with ALND. SLNB can improve activity of daily life (ADL) by improving of the upper limb function. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-14-01.