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Background: Previously, we conducted the 5-year open-label, randomized controlled trial (RCT) of leuprorelin adjuvant therapy in post-operative premenopausal patients with endocrine-responsive breast cancer, which was a pilot study to investigate the optimal duration of leuprorelin treatment. Since, however, long-term outcomes became required for the adjuvant endocrine therapy, we performed this follow-up observation study., Methods: Follow-up observation study was performed up to 10th year after randomization, continuing RCT to evaluate the efficacy and safety of leuprorelin every 3 months for ≥ 3 versus 2 years, with daily tamoxifen for 5 years. Primary endpoints were disease-free survival (DFS) and 2-year landmark DFS., Results: Eligible patients (N = 222) were randomly assigned to receive leuprorelin for either 2 years (N = 112) or ≥ 3 years (N = 110) with tamoxifen. Leuprorelin treatment for ≥ 3 years versus 2 years provided no significant difference in DFS (HR 0.944, 95% CI 0.486-1.8392) or 2-year landmark DFS (N = 99 and 102 in 2-year and ≥ 3-year groups, HR 0.834, 0.397-1.753). In small, higher-risk subgroup (n = 17); however, 2-year landmark DFS in ≥ 3-year group was significantly longer (HR 0.095, 0.011-0.850) than that in 2-year group. The incidence of bone-related adverse events was around 5% in both groups., Conclusions: Adjuvant leuprorelin treatment for ≥ 3 years with tamoxifen only showed similar efficacy and safety profiles to those for 2 years in analyses among all patients but suggested greater benefit in higher-risk patients. No new safety signal was identified for long-term leuprorelin treatment., Trial Registration Number: Not applicable. This was an observational study.

Background: Combined endocrine therapy with a cyclin-dependent kinase (CDK) 4/6 inhibitor has been indicated to improve not only progression-free survival, but also overall survival in patients with hormone receptor (HR)-positive, HER2-negative advanced breast cancer. However, resistance to this combination therapy inevitably develops. How to manage this resistant breast cancer is one of the most important clinical issues. To investigate the mechanisms of action responsible for resistance, we developed breast cancer cells resistant to CDK4/6 inhibitors, and analyzed their biological characteristics and sensitivity to different anticancer agents., Methods: HR-positive, HER2-negative MCF-7 and KPL-1 breast cancer cells were cultivated in palbociclib (PAL) or abemaciclib (ABE)-added culture medium for over 5 months, and we successfully developed PAL- or ABE-resistant cells. The effects of PAL or ABE on the cell growth, basal RB expression, RB phosphorylation, cell cycle and cell senescence were compared between resistant and parental cells. Effects of the other CDK4/6 inhibitor, different chemotherapeutic agents and estrogen on the cell growth were also examined. The expression levels of cyclin D1, CDK2, CDK4, CDK6, cyclin E1 and estrogen receptor (ER)-ɑ were measured using RT-PCR., Results: Long-term exposure to up to 200 nM PAL or ABE resulted in the development of PAL- or ABE-resistant MCF-7 or KPL-1 breast cancer cells. Basal expression levels of RB in both resistant cells were down-regulated. Inhibitory effects of either PAL or ABE on RB phosphorylation were reduced in both resistant cells. Accordingly, G1-S cell cycle retardation and cell senescence induced by either inhibitor were also attenuated in both resistant cells. Both resistant cells were cross-resistant to the other CDK4/6 inhibitor but almost as equally sensitive to different chemotherapeutic agents (5-fluorouracil, gemcitabine, paclitaxel, docetaxel, doxorubicin and eribulin) as the parental cells. The mRNA expression level of CDK6 significantly increased in the resistant MCF-7 cells and that of Rb1 significantly decreased in the resistant KPL-1 cells. Although both resistant cells were less sensitive to estrogen than the parental cells, the expression levels of ER-ɑ did not significantly change in either., Conclusions: Our study suggests that acquired resistance to PAL or ABE confers cross-resistance to the other CDK4/6 inhibitor but not to chemotherapeutic agents in HR-positive, HER2-negative breast cancer cells. Down-regulation of basal RB expression and normalized RB phosphorylation reduced by CDK4/6 inhibitors may be responsible for the attenuated anti-cell growth effects of the inhibitors.

Background: A cyclin-dependent kinase (CDK) 4/6 inhibitor, palbociclib, has been used to treat patients with estrogen receptor (ER)-positive (+) and human epidermal growth factor receptor (HER) 2-negative (-) advanced breast cancer. To investigate the mechanisms underlying the antitumor activity of palbociclib, we conducted a preclinical study on the anti-cell growth and anti-cancer stem cell (CSC) activity of palbociclib in breast cancer cells., Methods: The effects of palbociclib on Rb phosphorylation, cell growth, cell cycle progression, apoptosis, cell senescence and the proportion of CSCs were investigated in five human breast cancer cell lines of different subtypes. To investigate the mechanisms of the anti-CSC activity of palbociclib, small-interfering RNAs for CDK4 and/or CDK6 were used. Palbociclib dose-dependently reduced Rb phosphorylation and cell growth in association with G1-S cell cycle blockade and the induction of cell senescence, but without increased apoptosis, in all breast cancer cell lines., Results: The anti-cell growth activity of palbociclib widely differed among the cell lines. Palbociclib also dose-dependently reduced the CSC proportion measured by three different assays in four of five cell lines. The inhibition of CDK4 expression, but not CDK6 expression, reduced the increased proportion of putative CSCs induced by estradiol in ER (+)/HER2 (-) cell lines., Conclusions: These results suggest that palbociclib exhibits significant anti-cell growth and anti-CSC activity in not only ER (+) breast cancer cell lines but also ER (-) cell lines. CDK4 inhibition induced by palbociclib may be responsible for its anti-CSC activity.

Background: The hedgehog (Hh) signaling pathway plays important roles in cell proliferation, malignant progression, invasion and metastasis, and the expansion of cancer stem cells (CSCs). Comprehensive immunohistochemical (IHC) analyses have not yet been conducted on the expression levels of Hh signaling molecules in breast cancer tissues., Methods: A total of 204 patients with invasive breast cancer treated in our institute were study subjects. IHC analyses on the expression levels of the Hh signaling molecules, sonic Hh (SHH), PTCH1, GLI1, GLI2, and GLI3 and the CSC-related factor, SOX2, were investigated., Results: Positive correlations were observed among all of the Hh signaling molecules tested. SOX2 expression correlated with the expression levels of all Hh signaling molecules. SHH expression positively correlated with tumor size, the Ki-67 labeling index, histological grade, estrogen receptor negativity, progesterone receptor negativity, and HER2 positivity. GLI1 expression positively correlated with the histological grade. GLI2 expression positively correlated with the histological grade, Ki-67 labeling index, and HER2 positivity. Univariate analyses revealed that a younger age, larger tumor size, positive lymph node metastasis, higher histological grade, positive lymphatic invasion, and higher Ki-67 labeling index were related to poor relapse-free survival (RFS). The positivity of all Hh signaling molecules and SOX2 did not correlate with poor RFS. A multivariate analysis revealed that positive lymphatic invasion and a younger age were independent worse prognostic factors for RFS., Conclusions: This comprehensive analysis demonstrated for the first time that SHH, GLI1, and GLI2 expression levels positively correlated with the malignant phenotypes of tumor cells.

Background: Triple-negative breast cancer (TNBC) exhibits biologically aggressive behavior and has a poor prognosis. Novel molecular targeting agents are needed to control TNBC. Recent studies revealed that the non-canonical hedgehog (Hh) signaling pathway plays important roles in the regulation of cancer stem cells (CSCs) in breast cancer. Therefore, the anti-cell growth and anti-CSC effects of the non-canonical Hh inhibitor GANT61 were investigated in TNBC cells., Methods: The effects of GANT61 on cell growth, cell cycle progression, apoptosis, and the proportion of CSCs were investigated in three TNBC cell lines. Four ER-positive breast cancer cell lines were also used for comparisons. The expression levels of effector molecules in the Hh pathway: glioma-associated oncogene (GLI) 1 and GLI2, were measured. The combined effects of GANT61 and paclitaxel on anti-cell growth and anti-CSC activities were also investigated., Results: Basal expression levels of GLI1 and GLI2 were significantly higher in TNBC cells than in ER-positive breast cancer cells. GANT61 dose-dependently decreased cell growth in association with G1-S cell cycle retardation and increased apoptosis. GANT61 significantly decreased the CSC proportion in all TNBC cell lines. Paclitaxel decreased cell growth, but not the CSC proportion. Combined treatments of GANT61 and paclitaxel more than additively enhanced anti-cell growth and/or anti-CSC activities., Conclusions: The non-canonical Hh inhibitor GANT61 decreased not only cell growth, but also the CSC population in TNBC cells. GANT61 enhanced the anti-cell growth activity of paclitaxel in these cells. These results suggest for the first time that GANT61 has potential as a therapeutic agent in the treatment of patients with TNBC.

Background: Leuprorelin acetate, a luteinizing hormone-releasing hormone agonist, is used worldwide in premenopausal women with hormone receptor-positive breast cancer. This study was conducted to assess the non-inferiority of the 6-month depot formulation, TAP-144-SR (6M) 22.5 mg to the 3-month depot formulation, TAP-144-SR (3M) 11.25 mg in postoperative, premenopausal patients with hormone receptor-positive breast cancer., Methods: This was a 96-week phase III, randomized, open-label, parallel-group comparative study. All patients concomitantly received oral tamoxifen (20 mg daily). The primary endpoint was the suppression rate of serum estradiol (E 2 ) to the menopausal level (≤30 pg/mL) from Week 4 through Week 48., Results: In total, 167 patients were randomized to receive TAP-144-SR (6M) (n = 83) or TAP-144-SR (3M) (n = 84) and the E 2 suppression rate was 97.6 and 96.4 %, respectively. The estimated between-group difference was 1.2 % (95 % confidence interval -5.2 to 7.8). The non-inferiority of TAP-144-SR (6M) to TAP-144-SR (3M) for E 2 suppression was confirmed. As for safety, common adverse events were hot flush and injection site reactions including induration, pain, and erythema in both treatment groups, which were of ≤Grade 2 in severity and not serious. No significant between-group differences in safety profiles and tolerability were observed., Conclusions: TAP-144-SR (6M) was not inferior to TAP-144-SR (3M) for its suppressive effect on serum E 2 . TAP-144-SR (6M) was also as well tolerated as TAP-144-SR (3M)., Competing Interests: J. Kurebayashi received advisory/consultation fees from Takeda Pharmaceutical Company Limited and research funding from Takeda Pharmaceutical Company Limited, Eisai Company Limited, Chugai Pharmaceutical Company Limited and AstraZeneca K.K. T. Toyama received a research funding from Takeda Pharmaceutical Co., Ltd., Daiichi Sankyo Healthcare Co., Ltd. and Novartis Pharma K.K. S. Sumino, E. Miyajima and T. Fujimoto are employees of Takeda Pharmaceutical Company Limited. This work was supported by Takeda Pharmaceutical Company Limited.

Background: Luteinizing hormone-releasing hormone (LH-RH) agonists provide effective adjuvant treatment for premenopausal women with endocrine-responsive breast cancer. Here, we investigated appropriate treatment durations of an LH-RH agonist, leuprorelin., Methods: We conducted an open-label, randomized controlled pilot study to evaluate the safety and efficacy of leuprorelin subcutaneously administered every-3-months for 2 versus 3 or more, up to 5 years, together with daily tamoxifen for 5 years in premenopausal endocrine-responsive breast cancer patients. Primary endpoints were disease-free survival (DFS) and safety., Results: Eligible patients (N = 222) were randomly assigned to receive leuprorelin for either 2 years (N = 112) or 3 or more years (N = 110) with tamoxifen for 5 years after surgery. Leuprorelin treatment for 3 or more years provided no significant difference in DFS rate over 2 years: 94.1 versus 91.8 % at 144 weeks (3 years) after the second year (week 96) and 90.8 versus 90.4 % at the fifth year (week 240). The overall survival rate was 100 % for both groups during the third through fifth year study period. There were no significant differences in the incidence of adverse events (AEs) between the 2 groups: most AEs were rated grade 1 or 2., Conclusions: Adjuvant leuprorelin treatment for 3 or more years with tamoxifen showed a survival benefit and safety profile similar to that for 2 years in premenopausal endocrine-responsive breast cancer patients. No new safety signal was identified for long-term leuprorelin treatment. Longer follow-up observation is needed to determine the optimal duration of leuprorelin treatment.

Background: Eribulin mesylate (eribulin), a non-taxane microtubule dynamic inhibitor, has been widely used in the treatment of patients with advanced or metastatic breast cancer. The combined antitumor and anticancer stem cell (CSC) activities of eribulin with endocrine therapeutic agents have not yet been examined in breast cancer cells. We herein investigated the combined effects of eribulin and antiestrogens., Methods: A panel of eight breast cancer cell lines, including five estrogen receptor (ER)-positive and three ER-negative cell lines, was used. These cells were treated with eribulin and/or the antiestrogen, 4-hydroxytamoxifen or fulvestrant. Their growth inhibitory activities and effects on cell cycle progression, apoptosis, and the CSC population were investigated. CSCs were detected using the CD44/CD24/EpCAM, Aldefluor, and mammosphere assays., Results: The 50% growth inhibitory concentrations of eribulin were 0.38-2.64 nM for the eight cell lines tested. Eribulin exhibited significant antitumor activity under estrogen-supplemented conditions in ER-positive breast cancer cells. The combined antitumor activity of eribulin with an antiestrogen was evaluated using the combination index. The combination index was 0.43-1.46 for ER-positive cell lines. The additive antitumor effect of eribulin with 4-OHT was only significant in MCF-7 cells. Eribulin induced the accumulation of G2/M and apoptosis, while antiestrogens induced the retardation of G1-S cell cycle and apoptosis, respectively. Estrogen markedly increased the proportion of CSCs, whereas antiestrogens inhibited increases in ER-positive cell lines. Moreover, eribulin decreased the proportion of CSCs in either ER-positive or ER-negative cell lines. The combined treatment of eribulin with an antiestrogen did not additively decrease the proportion of CSCs in ER-positive cell lines., Discussion: The results of the present study demonstrated that eribulin had potent antitumor effects on estrogen-stimulated ER-positive breast cancer cells and the combined treatment of eribulin with an antiestrogen resulted in a weakly additive antitumor effect. We herein suggested for the first time that eribulin exhibited anti-CSC effects on either ER-positive or ER-negative breast cancer cells.

Background: Adjuvant trastuzumab has been routinely used in HER2-positive operable breast cancer patients. Prognostic factors remain to be well characterized in these patients and might correlate with primary and/or acquired resistance to trastuzumab., Patients and Methods: The study subjects were 78 HER2-positive operable breast cancer patients treated with adjuvant chemotherapy followed by 1-year trastuzumab between 2005 and 2010 in our institute. All breast tumors showed a HercepTest score of 3+ or that of 2+ and positive fluorescence in situ hybridization. Expression levels of HER1, phosphorylated HER2 (pY1248), HER3, HER4, and p53 were assessed by immunohistochemistry. Prognostic factors were investigated with univariate and multivariate analyses using the Kaplan-Meier/log-rank test and Cox proportional hazards model, respectively., Results: The median age and follow-up period of the patients were 54 years and 39 months, respectively. The mean tumor size was 2.1 cm and the node-positive rate was 42 %. Eight patients had recurrent diseases but no patient died of cancer. Univariate analysis revealed that pHER2 positivity was only a significantly worse prognostic factor for relapse-free survival (RFS) (P = 0.049). A HercepTest score of 2+ and high expression level of p53 showed a trend. Multivariate analysis revealed three biological markers: pHER2 positivity [hazard ratio (HR) = 11.6, 95 % confidence interval (CI) 1.3-111.1, P = 0.031], p53 positivity (HR = 6.4, 95 % CI 1.0-40.0, P = 0.047) and a HercepTest score of 2+ (HR = 8.6, 95 % CI 1.6-45.2, P = 0.011) to be worse prognostic factors for RFS. Notably, three out of five patients with breast tumors expressing HER2 at a score of 2+ and pHER2 had recurrent diseases. Interestingly, the expression level of pHER2 significantly correlated with the expression levels of HER2 and HER3 in HER2-positive breast tumors., Conclusions: This retrospective cohort study suggests that a lower expression level of HER2 and high expression levels of pHER2 and p53 may indicate a worse prognosis in HER2-positive breast cancer patients treated with trastuzumab and chemotherapy. Further studies are needed to evaluate pHER2 expression in HER2-positive breast cancer as a prognostic and/or predictive marker.

Purposes: We conducted a study to analyze the clinicopathological characteristics of breast cancer in Japan registered to the Japanese Breast Cancer Registry of the Japanese Breast Cancer Society (JBCS). Trends in the management of breast cancer patients in Japan were also analyzed., Patients and Methods: More than 250,000 breast cancer patients were registered to the JBCS registry between 2004 and 2011. Demographic and clinicopathological factors in newly diagnosed primary breast cancer patients were registered to the JBCS through the Web-based system from affiliated institutes nationwide., Results: Two distinct peaks were observed, in patients in their late 40s and early 60s, in the population-adjusted age distribution of breast cancer patients. An increased rate of screen-detected breast cancer may contribute to an earlier detection of breast cancer and increased rate of non-invasive ductal carcinoma. The positive rate of either ER or PgR appears to have increased in recent years. The annual rates of patients treated with breast-conserving surgery increased until 2006, but these increases stopped in 2007 and thereafter plateaued at approximately 60 %. The annual rates of patients treated with sentinel lymph node dissection alone have steadily increased. The annual rates of patients treated with preoperative trastuzumab plus chemotherapy have also increased, as well as those treated with postoperative aromatase inhibitors. The annual rates of patients treated with postoperative anthracycline-containing regimens have decreased, whereas those treated with postoperative taxane-containing regimens have increased. The postoperative use of trastuzumab has markedly increased since 2007., Conclusion: Although this study was based on the registry database, several unique clinicopathological characteristics of breast cancer in Japan have been unveiled. Our results suggest that recent trends in the management of breast cancer patients in Japan were strongly followed by clinical evidence that originated from a number of clinical trials worldwide.

Purpose: Whether postoperative chemotherapy should be added to endocrine therapy or not is an important issue in patients with hormone receptor-positive and human epidermal growth factor receptor (HER)2-negative breast cancer. To identify patients who should be treated with additional chemotherapy, prognostic factors were investigated in breast cancer patients postoperatively treated with endocrine therapy alone., Patients and Methods: Tumor samples and clinicopathological data were collected from patients who underwent curative surgery and were postoperatively treated with endocrine therapy alone between 1999 and 2003 in three different institutes. Expression levels of estrogen receptor (ER), progesterone receptor (PgR), and HER2 in primary tumors were centrally retested. Patients with ER-negative and/or HER2-positive tumors and/or with unknown nodal status were excluded from the study subjects. Immunohistochemical analysis of Ki67, HER1, insulin-like growth factor-1 receptor, and aldehyde dehydrogenase-1 was also performed. Prognostic factors were investigated by univariate and multivariate analyses., Results: A total of 261 patients were the subjects of this study. The median age was 59 years old, the mean tumor size was 1.9 cm, the node-positive rate was 20 %, and 65 % received tamoxifen alone. Distant metastases were observed in 11 patients at a median follow-up of 98 months, and four patients had died of breast cancer at a median follow-up of 99 months. Univariate analysis showed that marked lymphovascular invasion (LVI), PgR negativity, high Ki67 labeling index (LI), and high nuclear grade were significantly worse prognostic factors for distant metastasis. Multivariate analysis revealed that marked LVI [hazard ratio (HR) 21.8] and PgR negativity (HR 10.3) were independently worse prognostic factors for distant metastasis, respectively. Multivariate analysis also revealed that marked LVI (HR 287.3), PgR negativity (HR 25.1), and high Ki67 LI (HR 19.6) were independently worse prognostic factors for breast cancer-specific death, respectively., Conclusions: The results of this multi-institute cohort study indicated that endocrine therapy alone could not prevent distant metastasis in breast cancer patients with PgR-negative tumors and/or with tumors showing marked LVI or high cell proliferation. These patients may need postoperative adjuvant chemotherapy in addition to endocrine therapy.

Background: In Japan, there are still no reports of long-term outcome for hypofractionated radiotherapy to the whole breast after breast-conserving surgery (BCS). We report our institution's results from evaluation of the efficacy and safety of hypofractionated radiotherapy for Japanese women., Methods: Data in the medical records of 327 patients were retrospectively reviewed. The patients were treated with hypofractionated radiotherapy between January 2003 and December 2006 at the Kawasaki Medical School Hospital and were followed for more than 3 years. The median age was 54 years old (the age range was 28-80 years). The whole breast was irradiated with a total dose of 42.56 Gy/16 fx with boost irradiation to positive margins. Adjuvant therapy consisted of chemotherapy and/or hormone therapy and was administered to 300 patients, based on their stage or pathological findings., Results: Follow-up periods ranged from 21 to 92 months; the median follow-up period was 60 months. At 5-year follow-up, overall survival, cause-specific survival, relapse-free survival, and local control were 96.0, 97.5, 95.3, and 99.7% respectively. Grade 2 radiation pneumonitis occurred in five patients. Grade 2 radiation dermatitis occurred in 17 patients. Severe late complications were not observed., Conclusions: In our study, hypofractionated radiotherapy led to good results without severe toxicity. We believe hypofractionated radiotherapy after BCS is safe and efficient treatment for Japanese women.

Background: Although the poly adenosine diphosphate (ADP)-ribose polymerase (PARP) inhibitor olaparib is known to have potent antitumor activity in BRCA-related breast cancer cells, a limited number of preclinical and clinical studies have shown antitumor activity of olaparib in non-BRCA-related breast cancer. We investigated antitumor activity of olaparib in breast cancer cell lines derived from patients with nonfamilial sporadic breast cancer., Methods: Effects of olaparib alone or in combination with five different chemotherapeutic agents on cell growth, cell cycle progression, apoptosis, and proportion of cancer stem cells using the mammosphere assay and CD44/CD24/ESA cell surface marker assay were investigated in a panel of six sporadic breast cancer cell lines. Extracellular-signal-regulated kinase (ERK) phosphorylation was also investigated to elucidate action mechanisms of olaparib., Results: Olaparib inhibited the growth of two estrogen receptor (ER)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancer cell lines and two ER-negative and HER2-negative breast cancer cell lines (50% growth inhibitory concentrations 1.3-3.0 μM) associated with G2/M accumulation and induction of apoptosis. In contrast, two HER2-positive cell lines were resistant to olaparib. Interestingly, olaparib significantly decreased the proportion of putative cancer stem cells in either sensitive or resistant cell lines. In addition, olaparib increased expression of p-ERK. Combined treatments of olaparib with a mitogen-activated protein kinase kinase (MEK) inhibitor U0126 completely suppressed expression of p-ERK. These treatments also inhibited the G2/M accumulation and apoptosis induction by olaparib. Among five chemotherapeutic agents commonly used for breast cancer treatment, only an irinotecan metabolite SN38 showed additive antitumor activity with olaparib. Importantly, the combined treatment enhanced the increase in G2/M accumulation and apoptosis induction as well as a decrease in the proportion of cancer stem cells., Conclusions: This study has indicated for the first time that the PARP inhibitor olaparib has substantial antitumor and anticancer stem cell activity in breast cancer cell lines of nonfamilial origin. Upregulation of p-ERK might explain, at least in part, antitumor and anticancer stem cell activity of olaparib. Combined treatment of olaparib with irinotecan might be effective in treatment of non-BRCA-related breast cancer.

Background: Triple negative (TN) breast cancer is defined as a subtype that is negative for estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor 2 (HER2). To clarify the characteristics of TN breast cancer, surveillance data of the Registration Committee of the Japanese Breast Cancer Society were analyzed., Method: Of 14,748 cases registered in 2004, 11,705 (79.4%) were examined for ER, PgR, and HER2. Of these, the most prevalent (53.8%) was a hormone-responsive subtype with ER positive/PgR positive/HER2 negative, followed by TN subtype (15.5%)., Results: The proportion of postmenopausal patients was relatively high in the TN subtype. This cancer was diagnosed at a slightly advanced stage and with more cases positive for lymph node metastases than other subtypes. Morphologically, the TN subtype was more frequently classified as solid-tubular carcinoma. Mucinous, tubular, or secretary carcinomas were frequently found in the hormone receptor positive/HER2 negative subtype, while squamous cell carcinoma, spindle cell carcinoma, and metaplastic carcinoma with bone/cartilage metaplasia were very frequently found in the TN group. Apocrine carcinoma was also found very frequently in the TN group. Selection of chemotherapy was not based on receptor subtypes, but was determined by the degree of tumor progression., Conclusions: Although TN types are similar to basal-like breast tumor, as determined by gene profiling, their diagnosis needs verification by determination of the level of epidermal growth factor receptor or cytokeratin 5/6 expression. TN type should be examined further for immunohistochemical features and analyzed for prognostic details in this cohort.

Predictive factors for anthracycline-based chemotherapy have yet to be incorporated into daily practice. Meta-analyses of studies using anthracycline-based treatment regimens have shown an improved prognosis for human epidermal growth factor receptor type 2 (HER2)-positive tumors, but not for HER2-negative tumors compared with results of non-anthracycline regimens. Currently it is believed that the positive association between HER2 status and anthracycline sensitivity is indirect, that is, their association may be mediated through topoisomerase II alpha (TOP2A), a target molecule of anthracyclines, since TOP2A is near HER-2 and co-amplification of the TOP2A gene frequently occurs in HER2-amplified tumors. This strongly suggests that TOP2A gene amplification is a predictive factor for anthracyline-based regimens. The Collaborative Study Group of Scientific Research of the Japanese Breast Cancer Society has demonstrated that TOP2A-positive and BRCA1-negative subsets evaluated by immunohistochemical staining show a significantly higher pathological complete response when treated with preoperative epirubicin-containing regimens. Combining these findings with the observation that triple-negative tumors and basal-like tumors respond to anthracycline treatment suggests that not only HER2-positive tumors but also a distinct subset of HER2-negative tumors may be sensitive to anthracycline-based regimens.

Background: Preoperative lymphoscintigraphy is commonly used in sentinel lymph node biopsy (SLNB) for patients with early breast cancer; however, its significance to predict SLN metastasis remains to be determined., Patients and Methods: Sixty patients were enrolled in a feasibility study of SLNB. Patients with clinically node-negative breast cancer were eligible for this study. Dynamic lymphoscintigraphy was performed before SLNB. All patients underwent SLNB followed by axillary lymph node dissection., Results: A dual mapping procedure using isotope and dye injections was performed. SLNs were identified in 59 of 60 patients (98.3%), with a node-positive rate of 41.7% and a false-negative rate of 1.7%. No SLN was identified in 4 of 60 patients (6.7%) on preoperative lymphoscintigraphy. Interestingly, abnormal accumulation of the radiotracer close to hot spots was observed in 29 of 56 patients (51.8%). Lymph node metastases were detected in 18 of 29 patients (62.0%) with this pattern and 5 of 27 patients (18.5%) without this pattern (P < 0.05). Micrometastases were more frequently detected in node-positive patients without this pattern than in those with this pattern (80 vs. 16.7%). Diagnostic parameters of this pattern to predict SLN metastases, including micrometastases, were 62.1% for sensitivity, 81.5% for specificity, and 71.4% for accuracy., Conclusions: Abnormal accumulation of the radiotracer close to radioactive spots may indicate SLN metastasis. When dynamic lymphoscintigraphy shows this pattern, surgeons should consider the presence of SLN metastasis and carefully remove additional lymph nodes surrounding radioactive lymph nodes so as not to leave metastatic SLNs behind.

The intrinsic subtype has demonstrated that breast cancers can be classified into biologically and clinically meaningful subgroups. Most breast tumors categorized as one of the intrinsic subtypes, i.e., basal-like, have an estrogen receptor-negative, progesterone receptor-negative, and human epidermal growth factor receptor 2-negative phenotype, so-called triple-negative (TN) phenotype; however, TN breast cancer is not a synonym for basal-like subtype. TN breast cancers account for 10-20% of all breast cancers, and are more biologically aggressive than breast cancers of other subgroups. Tailored therapies, such as endocrine therapy and anti-HER2 therapy, are not applicable to TN breast cancer. To develop novel strategies against TN breast cancer, it is essential to understand the specific pathways driving the aggressive behavior of TN breast cancer. Preclinical and clinical studies have suggested that DNA-damaging agents and poly ADP-ribose polymerase inhibitors are active in TN breast cancer harboring BRCA1 dysfunction; anti-epidermal growth factor receptor (EGFR) antibodies and EGFR tyrosine kinase inhibitors are active in TN breast cancer with EGFR gene amplification; dasatinib is active in TN breast cancer with activated Src tyrosine kinases; inhibitors of a mammalian target of rapamycin are active in TN breast cancer with loss of PTEN tumor suppressor; antiangiogenic therapies enhance antitumor activity of chemotherapeutic agents in hypervascular TN breast cancer; and irinotecan, trabectedin, ixabepilone, and ABI-007 are active in TN breast cancer. A number of clinical trials are ongoing to clarify the antitumor activity of these challenging treatment strategies. Further biological characterization of TN breast cancer is needed to develop more specific treatment strategies against TN breast cancer.

Breast cancer is a hormone-dependent cancer like prostate cancer and endometrial cancer. Estrogen plays important roles in the development and progression of breast cancer. Endocrine therapy is the treatment of choice for estrogen receptor- and/or progesterone receptor-positive breast cancer. Endocrine therapy has been used for several purposes, including chemoprevention, preoperative treatment, postoperative adjuvant treatment and treatment for recurrent diseases. A large number of clinical trials have provided evidence showing the clinical benefits of various endocrine therapies for the treatment of breast cancer. The current status and recent advances in endocrine therapy for breast cancer are reviewed based on the results of current clinical trials. Future perspectives of endocrine therapy are also discussed.

Objective: The significance of serum tumor markers in monitoring advanced breast cancer patients is still controversial. To clarify this issue, the Tumor Marker Study Group of the Japanese Breast Cancer Society conducted a prospective study., Methods: Patients with advanced breast cancer who were treated with systemic therapy between January and December 2002 were recruited from five collaborative institutes in Japan. The patients were monitored every four weeks using three serum tumor markers, CEA, CA 15-3 and NCC-ST-439 during the therapy., Results: Findings from 108 eligible patients were analyzed. The pretreatment positivity rates were 51.9% for CEA, 50% for CA 15-3, and 34.3% for NCC-ST-439. The changes in each marker level at 8 and 12 weeks but not at 4 weeks after the start of therapy seemed to correlate with the response to therapy in pretreatment marker-positive patients but not in negative patients. The Cox proportional hazard model revealed a greater than 20% reduction in CEA, CA 15-3 or NCC-ST-439 levels at 4, 8 and/or 12 weeks after the start of therapy to be an independent predictive factor for longer time-to-progression (TTP) in pretreatment marker-positive patients., Conclusion: This prospective study supported the findings obtained from our previous retrospective study that in pretreatment marker-positive patients 1) the changes in serum tumor marker levels after the start of therapy correlate with the response to therapy; and 2) a greater than 20% reduction in the tumor marker levels was a favorable predictive factor for TTP during systemic therapy. When the pretreatment serum level of these markers is over the respective cut-off value, sequential measurement of them may be useful for evaluating the efficacy of treatment as well as monitoring the outcome of patients with advanced breast cancer.

Epidermal growth factor receptor (EGFR)/HER1 is expressed at high levels in at least 20% of breast cancers. This high expression correlates with a poor prognosis in patients with breast cancer. Experimental and clinical findings suggest that aberrant activation of tyrosine receptor kinases, such as HER1 pathway, play a causal role in the development of antiestrogen resistance in breast cancer. Recent preclinical and clinical evidence shows that inhibition of growth factor signaling pathways suppresses the growth of malignant cells without serious toxicities. To test the hypothesis that inhibition of the HER1 signaling pathway enhances the antitumor effect of endocrine therapy, a promising signal transduction inhibitor (STI) of HER1 tyrosine kinase, gefitinib, and an estrogen receptor (ER) antagonist, fulvestrant, were administered to human breast cancer cells. Our experimental results have revealed that gefitinib additively enhances the antitumor effect of fulvestrant in estrogen receptor (ER)-positive breast cancer cells under estrogen-supplemented conditions. An additive increase in the protein expression level of a cyclin-dependent kinase inhibitor, p21 may play a key role of this additive cytostatic effect. The rationale and future perspectives of the combined use of STIs with endocrine therapy in breast cancer are discussed.

Objective: The significance of serum carcinoembryonic antigen (CEA) and CA 15-3 in monitoring advanced breast cancer is still controversial. To clarify this issue, the Tumor Marker Study Group of the Japanese Breast Cancer Society conducted a large-scaled retrospective study., Methods: The findings from four clinical trials and seven institutes of 528 patients with advanced breast cancer were collected. Three-hundred forty-eight patients, in whom both serum CEA and CA 15-3 were measured during therapy, were selected for analysis., Results: The pretreatment positivity rate of CA 15-3 was significantly higher than that of CEA (p<0.0001). Time-to-progression (TTP) in CEA- and CA 15-3-positive patients was significantly shorter than TTP in negative patients. The changes in either marker level correlated well with response to therapy in marker-positive patients but not in negative patients. TTP in the marker-positive patients with a greater than 20%-reduction in either marker level during therapy was significantly longer than that in positive patients without such a reduction (p<0.01 for CEA and CA 15-3)., Conclusion: CA 15-3 is more useful for monitoring advanced breast cancer than CEA and a greater than 20%-reduction in marker levels suggests longer TTP in pretreatment marker-positive patients.

Estrogen plays important roles in the development and progression of breast cancer. However, one-third of breast cancers fail to respond to endocrine therapy and most endocrine-responsive breast cancers subsequently become resistant to endocrine therapy. A tremendous effort has been made to elucidate the mechanisms responsible for the development of endocrine-resistance in breast cancer. Since the main target molecule of estrogen in breast cancer is estrogen receptor (ER)-alpha, most studies have focused on investigating quantitative and qualitative changes in ER-alpha in endocrine-resistant breast cancer. Breast cancers expressing no ER-alpha fail to respond to endocrine therapy. Some breast cancers expressing ER-alpha also fail to respond to endocrine therapy and most breast cancers with acquired endocrine resistance retain ER-alpha expression, which suggests that the disappearance of ER-alpha in breast cancer cells is not a common cause of resistance to endocrine therapy. Recent molecular biological studies have shown evidence that qualitative and functional changes, such as gene mutations and phosphorylation of ER-alpha, cause endocrine resistance in breast cancer. In addition, it has been suggested that endocrine resistance could be induced by epigenetic changes, such as hypoxia, in breast cancer tissues. Understanding the precise mechanisms that underlie endocrine resistance may enable clinicians to develop new strategies for retarding or overcoming endocrine resistance in breast cancer.

The product of the HER-2/neu proto-oncogene, HER2, is the second member of the human epidermal growth factor receptor (HER) family of tyrosine kinase receptors and has been suggested to be a ligand orphan receptor. Ligand-dependent heterodimerization between HER2 and another HER family member, HER1, HER3 or HER4, activates the HER2 signaling pathway. The intracellular signaling pathway of HER2 is thought to involve ras-MAPK, MAPK-independent S6 kinase and phospholipase C-gamma signaling pathways. However, the biological consequences of the activation of these pathways are not yet completely known. Amplification of the HER2 gene and overexpression of the HER2 protein induces cell transformation and has been demonstrated in 10% to 40% of human breast cancer. HER2 overexpression has been suggested to associate with tumor aggressiveness, prognosis and responsiveness to hormonal and cytotoxic agents in breast cancer patients. These findings indicate that HER2 is an appropriate target for tumor-specific therapies. A number of approaches have been investigated: (1) a humanized monoclonal antibody against HER2, rhuMAbHER2 (trastuzumab), which is already approved for clinical use in the treatment of patients with metastatic breast cancer; (2) tyrosine kinase inhibitors, such as emodin, which block HER2 phosphorylation and its intracellullar signaling; (3) active immunotherapy, such as vaccination; and (4) heat shock protein (Hsp) 90-associated signal inhibitors, such as radicicol derivatives, which induce degradation of tyrosine kinase receptors, such as HER2.

Interleukin (IL)-6 may play possible roles in the proliferation and metastasis of cancer cells, in the development of osteolysis and humoral hypercalcemia, and in the regulation of estrogen production in breast cancer tissues. IL-6 is also suggested to be a cachectic factor in cancer patients. A decrease in serum IL-6 levels induced by medroxyprogesterone acetate (MPA) has been reported to correlate with a reversion of body weight loss in patients with advanced breast cancer. To elucidate the mechanisms of action of the anti-cachectic effect of MPA its effects on IL-6 secretion from the KPL-4 cell line, the first human breast cancer cell line to secrete IL-6 and to induce cachexia, were explored. It has been suggested that an inhibitory effect of MPA on IL-6 secretion from breast cancer cells causes the anti-cachectic effect of MPA. Our other studies have revealed that 5'-fluorouridine (5'-DFUR) inhibits the growth of KPL-4 tumors and decreases IL-6 levels in both serum and tumor tissues. Decreasing serum IL-6 levels resulted in alleviation of body weight loss. Docetaxel increased IL-6 levels in both serum and KPL-4 tumors, but combined treatment with docetaxel and 5'-DFUR resulted not only in a potent antitumor effect but also in a drastic decrease of serum IL-6 levels. In the present paper the possible roles of IL-6 in the development and progression of breast cancer are reviewed, and the regulatory mechanisms of IL-6 secretion from breast cancer cells and the possible clinical implications of decreasing IL-6 secretion by therapeutic agents are discussed.

We employed interstitial brachytherapy using a high dose rate Ir-192 remote afterloading unit in two breast cancer patients with locoregional recurrence. In the first case, skin metastasis was treated, with favorable control of the infield tumor but subsequent persistent sequelae and multiple outfield metastases. This experience caused us to be cautious when choosing brachytherapy for the second case, in whom a solitary metastasis to an axillary lymph node was successfully treated. Although this method is still investigational, it may play a critical role in the treatment of locoregional recurrence resistant to other treatment modalities.

Predictive markers and variables for response to anticancer therapy provide cancer patients with refinement of therapeutic options and a decreased likelihood of receiving an ineffective therapy. The best-established predictive marker for response to endocrine therapy for breast cancer is the status of estrogen receptors (ER) in the primary breast tumor. However, although patients with ER-positive tumors have a greater than 50% objective response rate to endocrine therapy, other patients can not obtain an objective response. Therefore additional markers, such as better molecular biologic markers, are needed. Our previous study using multivariate analysis revealed that the ER status of primary tumors and the dominant site of metastasis are independent predictors for response to first-line endocrine therapy and that a response to first-line endocrine therapy is only an independent predictor for response to second-line endocrine therapy. However, all these factors are already well-established predictive markers for response to endocrine therapy. Recently, a number of new hormonal agents, such as more selective aromatase inhibitors and specific antiestrogens, have been developed and introduced. However, several questions, such as the best sequences when using hormonal agents, remain to be elucidated. On the other hand, several molecular biologic markers predicting response to endocrine therapy, such as the expression of the HER family of tyrosine kinase receptors, pS2, Bcl-2, and vascular endothelial growth factor, have been reported. To elucidate the most effective use of endocrine therapy for recurrent breast cancer, classical and new predictive factors for response to endocrine therapy are reviewed, and the clinical implications of these factors are discussed.

BACKGROUND: Four different endocrine therapeutic agents have been used in Japan since 1996. However, a consensus regarding proper use of these agents has notyet been established. Therefore, a questionaire survey of Japanese breast cancer authorities on endocrine therapy and a multi-institute survey to investigate the efficacy of a single first-line endocrine therapy for recurrent breast cancerwere conducted. MATERIALS AND PATIENTS: A total of 279 questionaires were sent to the Councilors of the Japanese Breast Cancer Society. The clinico-pathological data of 77 breast cancer patients who underwent a single first-line endocrine therapy were collected from five institutes. RESULTS: The response rate to this questionaire survey was 67.4%. The resultsshow that many authorities consider that: 1) both ER and PgR in primary tumors should be measured, 2) patient age, the disease-free interval and postoperative adjuvant therapy do not provide enough information for the selection of endocrine therapies, 3) antiestrogen and LH-RH agonists should be used as first-line endocrine therapies, 4) combined endocrine therapies, such as an antiestrogen plus an LH-RH agonist, should be used, 5) the optimal sequence of use of endocrine therapeutic agents is most controversial. The objective response rate to first-line endocrine therapies was 40.3% and the duration of response was over 15 months.The objective response rate to second-line endocrine therapies was 42.1%. A multiple regression analysis of predictive factors for the efficacy of first-line endocrine therapies indicated two factors, the disease-free interval and dominantsite of metastasis, to be significant. Conclusions: This questionaire survey suggests that clinical trials to investigate the optimal sequence of use of endocrine therapies and to clarify the usefulness of combined endocrine therapies should be conducted. Single first- or second-line endocrine therapies for recurrent breast cancer are effective and should be carried out by general clinicians.

From January 1987 to December 1993, Stage I (T1N0M0) breast cancers were treated by quadrantectomy with axillary lymph node dissection plus radiation therapy (QUART) in 57 cases and by modified radical mastectomy (MRM) in 57 cases. The results for these two treatment groups were compared retrospectively. Booster irradiation of 10 Gy to the tumor bed was given to 1 of 5 cases with a positive resection margin. The remaining 56 cases received 50 Gy lineac X-ray to the ipsilateral breast. Systemic adjuvant therapy, tamoxifen and /or 5-FU derivatives p.o., were given to the majority of cases in both groups. There were no significant differences between the two groups with regard to the patient background; ie, age, tumor size, pathological node status, histology and estrogen receptor status. During the follow-up period of 12 to 89 months (median 55 months) in the QUART group, no local recurrence was observed and only 1 case of bone metastasis occurred. In the MRM group, recurrence occurred in 4 cases during the follow-up period of 12 to 95 months (median 52 months). These consisted of 2 cases of regional lymph node recurrence and 2 cases of lung metastases. The differences in the disease-free survival rate and the overall survival rate between the two groups were not significant. In the QUART group, mild radiation pneumonitis and mild telangiectasia in the breast skin were observed in 2 cases(3.5%) and 1 case, respectively. Mild arm edema was observed in 4 cases (7%) in each group. These results demonstrated that QUART was as effective as MRM in treating T1M0M0 breast carcinoma in Japanese women.

The quality of life (QOL) in 55 early-stage breast cancer patients after surgery was prospectively assessed using a newly developed Japanese QOL questionnaire: The QOL Questionnaire for Cancer Patients Treated with Anticancer Drugs (QOL-ACD). The impacts of breast conserving treatment (BCT) (22 cases) and modified radical mastectomy (MRM) (33 cases) on the QOL in those subjects were compared. The overallQOL scores were evaluated during four periods (before surgery, 0-2, 3-12, and 13-24 months after surgery). The mean scores of the four categories of the QOL-ACD (activity, physical condition, psychological condition, and social relationships) were also compared. The results demonstrated that a significant improvement was observed in the overall QOL scores among the three periods after surgery (0-2, 3-12, and 13-24 months) only in the BCT group (p<0.05). There were no significant differences between the two groups in the overall QOL scores during any of the three periods after surgery, and the mean score of the 'psychological condition' during 0-2 months period in the BCT group was significantly lower than that in the MRM group (p<0.05). These results suggest that BCT does not always improve the patients' QOL more than MRM does, and that the patients receiving BCT require more psychological support than those receiving MRM during the early postoperative period.

The objective of this study was to investigate the factors associated with the quality of life (QOL) in breast cancer patients after surgery. The QOL in 83 primary breast cancer patients after surgery was prospectively assessed using a newly developed Japanese QOL questionnaire: The QOL Questionnaire for Cancer Patients Treated with Anticancer Drugs (QOL-ACD). The demographic and medical factors relating to the QOL score in the subjects were investigated by multiple regression analyses. Factors related to the four categories of the QOL-ACE (activity, physical condition, psychological condition, and social relationship) were also analyzed. The results revealed that only hospitalization had a strong negative relation to the overall QOL score. With regard to the four categories of the QOL-ACE, hospitalization had strong negative relations to the three categories (activity, physical condition and social relationship) and had weak negative relation to the psychological condition. Other demographic and medical factors such as types of surgery or adjuvant therapy had no significant association with the QOL score, except for the performance status which had positive, but not significant, association with the activity. In conclusion, this study yielded useful information concerning the management of the breast cancer patients after surgery. We had better be more concerned with the hospitalized period than other demographic or medical factors such as types of therapy to improve the QOL.

Accumulated knwoledge regarding the important roles played by angiogenesis in solid tumor growth and metastasis has prompted the development of angiogenesis inhibitors for clinical use in cancer therapy. Among these inhibitors, O-(chloroacetyl-carbamoyl) fumagillol (TNP-470) has been reported to have both antitumor and antimetastatic activities in rodent and human tumor models. We recently established a new metastasis model of MKL-4 human breast cancer cells in female nude mice. This cell line is a co-transfectant of the MCF-7 cell line with genes of a potent angiogenic factor, fibroblast growth factor 4, and a genetic marker, bacterial lac ¤ In this paper, we describe the inhibitory effects of TNP-470 on tumor angiogenesis, growth and metastasis in this MKL-4 metastasis model. Subcutaneous injection of 10 or 50 mg/kg of TNP-470 every other day for two weeks obviously inhibited the tumor growth and metastasis of MKL-4 cells in female nude mice. The treatment of TNP-470 at both doses significantly reduced the tumor volumes, respectively, to 28% and 14% of that in the control group(p<0.05 in each comparison). The positive rate of metastasis into the axillary lymph nodes was 100% in the control group, whereas it was only 33% in both of the treatment groups. Distant metastasis into the inguinal lymph nodes, lungs, kidneys and liver also tended to decrease in both of the treatment groups. Immunohistochemical analysis using anti-factor VIII antibody revealed that the number of microvessels in both of the treatment groups was significantly less than that in the control group(p<0.01 in each comparison). To the best of our knowledge, this is the first report describing simultaneous demonstration of the antiangiogenic, antitumor and antimetastatic effects of TNP-470 on human breast cancer cells in nude mice.