Takaaki Oba

Breast metastases of gastric signet-ring cell carcinoma: a report of two cases and review of the literature.

It is occasionally difficult to diagnose breast metastasis of gastric carcinoma because of its rarity. However, to appropriately treat patients with breast tumors without delay, it is important to distinguish metastatic cancer from primary breast cancer. We report two cases of breast metastasis of gastric carcinoma and review the literature. The first case was a 41-year-old female diagnosed with bilateral pelvic tumors who visited the outpatient clinic because of pain and enlargement of both breasts. Ultrasonography showed diffuse hypoechoic lesions, which were enhanced on gadolinium-enhanced magnetic resonance imaging in the bilateral mammary gland. Core needle biopsy of the right breast revealed signet-ring cells, which were also identified in the resected bilateral pelvic tumors. Subsequent upper gastrointestinal endoscopy revealed signet-ring cell carcinoma in the stomach, and the bilateral breast lesions were diagnosed as metastases of gastric carcinoma. The second case was a 34-year-old female diagnosed with cervical metastasis of signet-ring cell carcinoma who was referred to the breast cancer clinic because of a nodule in the left breast detected by computed tomography. Ultrasonography showed a hypoechoic nodule that was enhanced on gadolinium-enhanced magnetic resonance imaging. Because the pathologic findings for the left breast nodule were quite similar to those of gastric cancer and its cervical metastasis, the breast nodule was diagnosed as a metastasis of gastric carcinoma. When a breast tumor is suspected to have metastasized from a primary tumor in another organ, particularly if signet-ring cells are found, the possibility that gastric cancer is present should be considered.

ABCB1 and ABCC11 confer resistance to eribulin in breast cancer cell lines

This study aimed to elucidate the mechanisms underlying the resistance of breast cancer to eribulin. Seven eribulin-resistant breast cancer cell lines (MCF7/E, BT474/E, ZR75-1/E, SKBR3/E, MDA-MB-231/E, Hs578T/E, and MDA-MB-157/E) were established. mRNA and protein expression of ATP-binding cassette subfamily B member 1 (ABCB1) and subfamily C member 11 (ABCC11) increased in all eribulin-resistant cell lines compared to the parental cell lines. When ABCB1 or ABCC11 expression was inhibited by small interfering RNA in MCF7/E, BT474/E, and MDA-MB-231/E cells, eribulin sensitivity was partially restored. Moreover, eribulin resistance was attenuated additively by inhibiting ABCB1 and ABCC11 in MCF7/E cells. Additionally, overexpression of exogenous ABCB1 or ABCC11 in HEK293T cells conferred resistance to eribulin. MCF7/E and MDA-MB-231/E cells showed cross-resistance to paclitaxel, doxorubicin, and fluorouracil. Inhibition of ABCB1 partially restored paclitaxel and doxorubicin sensitivity. Partial restoration of fluorouracil sensitivity was induced by inhibiting ABCC11 in MCF7/E and MDA-MB-231/E cells. Both ABCB1 and ABCC11 are involved in the development of eribulin resistance in breast cancer cells in vitro regardless of the breast cancer subtype. Thus, ABCB1 and ABCC11 expression may be used as a biomarker for predicting the response to eribulin in patients with breast cancer. Concomitant inhibition of ABCB1 and ABCC11 might help enhance the antitumor effects of eribulin.

Lipid-rich carcinoma of the breast that is strongly positive for estrogen receptor: a case report and literature review.

Lipid-rich carcinoma (LRC) of the breast is a rare breast cancer variant that accounts for <1% of all breast malignancies. It has been reported that LRCs are negative for estrogen receptor. Here, we report a case of LRC of the breast that was strongly positive for estrogen receptor and treated with endocrine adjuvant therapy. A 52-year-old postmenopausal female noticed a lump in her right breast by self-examination and presented to our hospital. Physical examination revealed an elastic 30 mm ×20 mm hard mass in the upper medial part of her right breast. The findings obtained using ultrasonography, mammography, and contrast-enhanced magnetic resonance imaging suggested breast cancer. Core needle biopsy resulted in the diagnosis of invasive carcinoma. The patient underwent mastectomy and sentinel lymph node biopsy. Histopathologically, the tumor cells were abundant in foamy cytoplasm. Because the presence of marked cytoplasmic lipid droplets was confirmed by Sudan IV staining and electron microscopic examination of the tumor and the lipid droplets were negative for periodic acid–Schiff staining, the tumor was diagnosed as an LRC. Immunohistochemically, estrogen and progesterone receptors of the tumor were strongly positive, human epidermal growth factor receptor type 2 was negative, and the ratio of Ki-67-positive cells was ~30%. After surgery, the patient underwent combination chemotherapy with anthracycline, cyclophosphamide, and 5-fluorouracil, followed by docetaxel. Thereafter, the pateint was treated with letrozole and has remained well for 24 months with no signs of recurrence.

Combination of two anti-tubulin agents, eribulin and paclitaxel, enhances anti-tumor effects on triple-negative breast cancer through mesenchymal-epithelial transition

Improved prognosis for triple-negative breast cancer (TNBC) has currently plateaued and the development of novel therapeutic strategies is required. Therefore, we aimed to explore the anti-tumor effect of eribulin and paclitaxel combination therapy for TNBC. The effect of eribulin and paclitaxel in combination was tested, with both concurrent and sequential administration, using four TNBC cell lines (MDA-MB-231, Hs578T, MDA-MB-157, and Mx-1) in vitro and in an MDA-MB-231 BALB/c-nu/nu mouse xenograft model. The expression of epithelial-mesenchymal phenotypic markers was analyzed by western blotting and immunohistochemical analyses. Simultaneous administration of eribulin and paclitaxel resulted in a synergistic anti-tumor effect with MDA-MB-231 and Hs578T cells, but not MDA-MB-157 and Mx-1 cells, in vitro. Moreover, pre-treatment with one drug significantly enhanced sensitivity to the subsequently administrated second drug in MDA-MB-231 and Hs578T cells. Eribulin increased E-cadherin expression and decreased the expression of mesenchymal markers in MDA-MB-231 and Hs578T cells. In contrast, paclitaxel increased the expression of mesenchymal markers. When epithelial-mesenchymal transition was induced by TGF-β1, eribulin sensitivity was enhanced. In contrast, a TGF-β receptor kinase inhibitor decreased eribulin sensitivity. In MDA-MB-231 tumor-bearing mice, concurrent administration of low doses of eribulin and paclitaxel significantly inhibited tumor growth compared to that with either monotherapy. Moreover, single administration of eribulin before the initiation of paclitaxel treatment decreased vimentin expression and reduced the average tumor volume in a mouse xenograft model. Eribulin and paclitaxel show synergistic anti-tumor effect by altering the epithelial-mesenchymal phenotype. This combination therapy could represent a novel therapeutic strategy for TNBC.

Chylous leakage after axillary lymph node dissection in a patient with breast cancer

A 69-year-old woman presented to our hospital with a lump in her left breast. The patient was diagnosed as having stage IIA breast cancer and underwent left mastectomy and axillary lymph node dissection. Axillary lymph nodes at levels I and II were dissected with the axillary vein as the superior border, the latissimus dorsi muscle as the lateral border, and the serratus anterior muscle as the medial border. No unusual events occurred during the operation. Two drains were placed anterior to the major pectoral muscle and the axillary cavity. The histological examination confirmed an invasive ductal carcinoma of 33 mm. Two metastatic lymph nodes were detected. Her postoperative course was uneventful. The patient had a normal diet on the first day after the surgery, and the drainage from the axillary cavity was serous. The drain anterior to the pectoralis major muscle was removed on postoperative day (POD) 3, and the drain in the axillary cavity was removed on POD 11. The patient was discharged on POD 12. On POD 14, the patient visited the outpatient clinic with a slight swelling of axilla. Fifteen milliliters of a milky fluid was aspirated by centesis of the axillary cavity. We took a wait-and-see approach. On POD 21, the patient presented again with swelling of the axilla, and 400 mL of milky fluid was aspirated by centesis (Figure 1). A biochemistry analysis of the drainage fluid revealed 2246 mg/dL of triglycerides. Chylous leakage was identified as the cause of the fluid collection. The patient was admitted to the hospital on POD 22 for conservative treatment. Compression of the axillary cavity by bandage was initiated under a food-deprived condition. The triglyceride concentration had decreased to 545 mg/dL on POD 26. The patient began a low-fat diet on POD 30 and compression of the axillary cavity was removed on POD 31. No accumulation of seroma or chyle in the axilla occurred after removing the compression. Chylous leakage after axillary dissection in breast cancer patients is a very rare complication because the thoracic duct usually has no direct anatomical relation to the axilla. To date, only 31 cases, including our case, have been reported in the literature. Because of its rarity, the appropriate management for chylous leakage of the axilla is controversial. The clinical features of the 31 cases are summarized in Table 1. Twenty-nine (93.5%) cases of chylous leakage occurred in the left axilla. The higher incidence on the left side may result from anatomical reasons: the thoracic duct begins in the abdomen in the left side, crosses the midline to the left side at the level of the aortic arch and continues ascending until it reaches the root of the neck where it joins the venous system. With regard to treatment, 25 (80.6%) patients recovered with conservative treatment and 6 (19.4%) patients received surgery. Conservative treatments such as drainage, diet control, and compression is believed to have been

A Case of Adenomyoepithelioma of the Breast Showing Strong Uptake of 18F‐Fluorodeoxyglucose on a Positron Emission Tomography

An adenomyoepithelioma of the breast is a rare tumor characterized by biphasic proliferation of both epithelial and myoepithelial cells. This tumor is generally considered as a benign neoplasm, and there are few reports describing the imaging features of this tumor through 18F‐fluorodeoxyglucose positron emission tomography (FDG‐PET). Here, we report a case of an adenomyoepithelioma that showed strong uptake of FDG on PET similar to that observed with a malignant tumor. A 73‐year‐old woman presented to our hospital with a 3.5‐cm, mobile, and elastic hard tumor in the upper area of the left breast. Although the findings of mammography, ultrasonography, and contrast‐enhanced magnetic resonance imaging suggested that the tumor was malignant, it was diagnosed as an adenomyoepithelioma by core needle biopsy. An invasive ductal carcinoma, 0.5‐cm in size, was detected in the medial upper area of the ipsilateral breast during an examination. Although FDG‐PET demonstrated no lymph node or distant metastases from the invasive ductal carcinoma, strong uptake of FDG was detected in the adenomyoepithelioma. Breast conserving surgery and sentinel lymph node biopsy for the invasive ductal carcinoma together with resection of the adenomyoepithelioma was performed. A diagnosis of adenomyoepithelioma was confirmed through histologic examination of the resected specimen. This case indicates that some adenomyoepitheliomas may show a strong uptake of FDG on PET, which resembles a malignant tumor.

Abstract 2112: ABCC11/MRP8 and ABCB1/MDR1 confer eribulin resistance to breast cancer cells

Background: Eribulin is a key drug for the patients with metastatic breast cancer; however, the mechanisms of how breast cancer cells become resistant to eribulin have not been fully elucidated. The purpose of this study is to analyze the mechanisms of eribulin resistance in breast cancer cells. Cell lines: Eribulin resistant cell lines were established for three estrogen receptor (ER) positive cell lines (MCF7/E, BT474/E,ZR75-1/E), three triple negative cell lines (MDA-MB-231/E, Hs578T/E, MDA-MB-157/E), and one HER2 positive cell line (SKBR3/E) by exposing to stepwise increased doses of eribulin. Results: The mRNA and protein expressions of both ABCC11 and ABCB1 were increased in all eribulin resistant cell lines regardless of their subtype. Inhibition of either ABCC11 or ABCB1 by small interfering RNA (siRNA) partially restored the sensitivity to eribulin in MCF7/E, BT474/E, and ZR75-1/E cells. Moreover, dual inhibition of ABCC11 and ABCB1 additively restored the sensitivity to eribulin in MCF7/E cells. On the other hand, overexpression of exogenous ABCC11 caused eribulin resistance in MCF7 and MDA-MB-231 cells (resistance ratio; MCF7; 13.8±0.85, MDA-MB-231; 11.4±0.74). Interestingly, inhibition of ER expression by siRNA or down regulation of ER by fluvestrant decreased ABCC11 expression and increased the sensitivity to eribulin in MCF7/E cells. Discussion: Our data demonstrates that ABCC11/MRP8 and ABCB1/MDR1 confer eribulin resistance to breast cancer cells regardless of their subtype; moreover, our data suggests the possibility of involvement of ER pathway in the regulation of ABCC11 expression in the ER positive breast cancer cells. Although further studies should be required, the expression of ABCC11/ABCB1 may be used as biomarkers for prediction of response to eribulin in breast cancer. In addition, the inhibition of ABCC11/ ABCB1 might be of service in a novel strategy to enhance the antitumor effect of eribulin. Citation Format: Takaaki Oba, Ken-ichi Ito, Shun’ichiro Taniguchi. ABCC11/MRP8 and ABCB1/MDR1 confer eribulin resistance to breast cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2112.

Abstract P5-08-13: Alteration of sensitivity to chemotherapeutic agents in tamoxifen resistant estrogen receptor positive breast cancer

Background: In the treatment of estrogen receptor (ER) positive recurrent breast cancer, sequential treatment with endocrine or chemotherapy is generally used. However, there is no indicator by which we can select the appropriate chemotherapeutic agent to the endocrine resistant breast cancer in the subsequent treatment. The purpose of this study is to examine whether a preceding endocrine therapy affects the sensitivity to subsequent chemotherapy in ER positive breast cancer cells. Materials and methods: Three ER positive breast cancer cell lines (T47D, MCF7, BT474) and their tamoxifen (TAM) resistant derivatives (T47D/T, MCF7/T, BT474/T) were established and analyzed for sensitivity to doxorubicin (DOX), 5FU and paclitaxel (PTX). The mRNA levels of factors related to drug sensitivity were analyzed by RT-PCR. Results: MCF7/T became more sensitive to DOX and 5FU compared with the parental MCF7. In addition, the apoptosis induced by 5FU was significantly increased in MCF7/T compared with the parental MCF7. On the other hand, no difference of sensitivity to chemotherapeutic agents was observed in T47D/T and BT474/T compared with their parental cell lines. In MCF7/T and T47D/T, the expressions of dihydropyrimidine dehydrogenase ( DPD) were significantly decreased compared with those in the parental cell lines, while no difference was observed in the expression of thymidine synthase (TS). The expression of thymidine phosphorylase (TP) was decreased in MCF7/T. Conclusion: Our data demonstrate that the sensitivity to 5FU might be altered in a subset of ER positive breast cancer cells, and suggest a possibility that the sensitivity to the chemotherapeutic agents might be modified by the preceding endocrine therapy in ER positive breast cancer cells. We are analyzing drug sensitivity in tumor-bearing mouse model and the data are going to be presented in the meeting. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-08-13.