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Recent genome-wide association studies have shown that many single-nucleotide polymorphisms (SNPs) are associated with breast cancer risk. However, it is often unclear how these SNPs are related to breast cancer. Analysis of associations between SNPs and phenotypes may be important for determining mechanisms of action, including carcinogenesis. In previous case–control studies, we found three SNPs (rs2046210, rs3757318, and rs3573318) associated with breast cancer risk in Japanese women. Among these SNPs, two (rs2046210 and rs3757318) are located at 6q25.1, in proximity to the estrogen receptor 1 gene (ESR1). Using data from these studies, we examined associations between factors related to breast cancer risk, such as height, weight, and breast density, and the three SNPs in cases and controls. We also investigated whether the SNPs correlated with breast cancer features, such as estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor type-2 (HER2) status, and clinical stage. There was a significant difference in mean height between risk and non-risk allele carriers for rs2046210 (156.0 ± 5.8 vs. 154.3 ± 5.5 cm, p = 0.002), and rs3757318 (155.8 ± 5.7 vs. 154.7 ± 5.6 cm, p = 0.035) in cases, but no significant associations between height and these SNPs in controls. There was also a significant difference in breast density between risk and non-risk allele carriers for rs2046210 (p = 0.040) and rs3757318 (p = 0.044) in cases. rs2046210 and rs3757318 risk allele carriers tended to have higher breast density in all subjects and in controls. In cases, rs3757318 risk allele carriers were also significantly more likely to be ER-negative compared to non-risk allele carriers (ER-positive rate: 77% vs. 84%, p = 0.036). SNPs rs2046210 and rs3757318, which are associated with breast cancer risk in Japanese women, were significantly associated with height and high breast density, and this association was particularly strong in those with breast cancer. These findings suggest that SNPs in the ESR1 gene region affect phenotypes such as height and breast density.

Purpose Second-line endocrine therapy (ET) for estrogen receptor (ER)-positive and human epidermal growth factor 2 (HER2)-negative metastatic breast cancer (MBC) is offered based on the response to first-line ET. However, no clinical trials have evaluated the efficacy and safety of secondary ETs in patients with poor responses to initial ET. This study evaluated the efficacy of second-line ET in ER-positive and HER2-negative postmenopausal MBC patients with low or very low sensitivity to initial ET. Methods This multicenter prospective observational cohort study evaluated the response of 49 patients to second-line ETs in postmenopausal MBC patients with low or very low sensitivity to initial ET. The primary endpoint was the clinical benefit rate (CBR) for 24 weeks. Results Of the 49 patients assessed, 40 (82%) received fulvestrant in the second line, 5 (10%) received selective estrogen receptor modulators, 3 (6%) received aromatase inhibitors (AIs) alone, and 1 received everolimus with a steroidal AI. The overall CBR was 44.9% [90% confidence interval (CI): 34.6–57.6, p = 0.009]; CBR demonstrated similar significance across the progesterone receptor-positive (n = 39, 51.3%, 90% CI: 39.6–65.2, p = 0.002), very low sensitivity (n = 17, 58.8%, 90% CI: 42.0–78.8, p = 0.003), and non-visceral metastases (n = 25, 48.0%, 90% CI: 34.1–65.9, p = 0.018) groups. The median progression-free survival was 7.1 months (95% CI: 5.6–10.6). Conclusion Second-line ET might be a viable treatment option for postmenopausal patients with MBC with low and very low sensitivity to initial ET. Future studies based on larger and independent cohorts are needed to validate these findings.

Mammography is the standard examination for breast cancer screening of woman aged ≥ 40 years. High breast density on mammography indicates that mammary gland parenchyma occupy a high percentage of the breast. The objective of this study was to investigate factors associated with breast density and the risk of high breast density for breast cancer. A multicenter case–control study was performed in 530 patients and 1043 controls. Breast density was classified as C1–C4 using the Breast Imaging Reporting and Data System (BI-RADS). Clinical factors were obtained from questionnaires or medical records, and the influence of each factor (breast density, menopausal status, body mass index (BMI), parity, presence or absence of breastfeeding history, age at menarche, age at first birth, and familial history of breast cancer) on breast cancer risk in all patients was calculated as an age-adjusted odds ratio (OR). Multivariate logistic regression analyses were then performed in all patients and in pre- and postmenopausal and BMI-stratified groups using factors with a significant age-adjusted OR as adjustment factors. Age-adjusted ORs for breast cancer were significant for breast density, BMI, parity, and breast feeding, but not for age at menarche, age at first birth, or family history of breast cancer. In multivariate analysis, there was a significant correlation between breast density and breast cancer in postmenopausal women (OR for C1 vs. C2 1.90 [95% CI 1.34–2.70]; C1 vs. C4 2.85 [95% CI 1.10–7.16]). This correlation was also significant in patients in the third BMI quartile (22.3–24.5 kg/m2) (OR for C1 vs. C4 8.76 [95% CI 2.38–42.47]); and fourth BMI quartile (>24.5 kg/m2) (OR for C1 vs. C2 1.92 [95% CI 1.17–3.15]; C1 vs. C4 11.89 [95% CI 1.56–245.17]). Breast density on mammography is a risk factor for breast cancer after adjustment for other risk factors. This risk is particularly high in postmenopausal women and those with a high BMI.

BACKGROUND: An understanding of health-related quality of life (HRQOL) is of utmost importance in both oncological and esthetic breast surgery. The BREAST-Q is a patient-reported outcome (PRO) measure that investigates HRQOL and patient satisfaction before and after breast surgery. The aim of this study was to develop a Japanese version of the BREAST-Q including the mastectomy module, the reconstruction module, the augmentation module and the reduction/mastopexy module, and to assess the psychometric properties of the mastectomy module among Japanese women. METHODS: The Japanese version of the BREAST-Q was developed through forward translation, backward translation and patient testing. Traditional psychometric testing of the mastectomy module was administered to 45 post-mastectomy patients. RESULTS: The mastectomy, reconstruction, augmentation and reduction/mastopexy modules were formally developed into Japanese. Despite cultural difference between Japanese women and original target population, the contents were considered to be valid among Japanese woman. With the exception of the sexual well-being subscale, good reliability and validity were evident for the mastectomy module (Test-retest reliability 0.76-0.95, Chronbach's alpha coefficient 0.77-0.98). CONCLUSIONS: The BREAST-Q Japanese version is a useful PRO measure for investigating the impact of breast surgery on HRQOL and patient satisfaction. Further validation in younger Japanese women is needed to determine the usefulness of the sexual well-being subscale.

Recent studies have suggested that the association between smoking and breast cancer risk might be modified by polymorphisms in the N-acetyltransferase 2 gene (NAT2). Most of these studies were conducted in Western countries, with few reports from East Asia. We conducted a case–control study of 511 breast cancer cases and 527 unmatched healthy controls from December 2010 to November 2011 in Japan. Unconditional logistic regression was used to analyze the association of smoking with breast cancer risk stratified by NAT2 phenotype. In this population, 11 % of the cases and 10 % of the controls were classified as a slow acetylator phenotype. Compared to never smokers, current smokers had an increased breast cancer risk in multivariate analysis [odds ratio (OR) = 2.27, 95 % confidence interval (95 %CI) = 1.38–3.82]. Subgroup analyses of menopausal status indicated the same tendency. Subgroup analyses of NAT2 phenotype, the ORs in both of rapid and slow acetylator phenotype subgroups were comparable, and no interactions were observed between smoking status and NAT2 phenotype (p = 0.97). A dose-dependent effect of smoking on breast cancer risk was seen for the rapid acetylator phenotype, but not for the slow acetylator phenotype. Given the high frequency of the rapid acetylator phenotype, these results show that smoking is a risk factor for breast cancer among most Japanese women. It may be of little significance to identify the NAT2 phenotype in the Japanese population.

Aldehyde dehydrogenase 1 (ALDH1) is a marker of breast cancer stem cells, and the expression of ALDH1 may be a prognostic factor of poor clinical outcome. The epithelial-mesenchymal transition may produce cells with stem-cell-like properties promoted by transcription factors. We investigated the expression of ALDH1 and transcription factors in both primary and metastatic lesions, and prognostic value of them in breast cancer patients with axillary lymph node metastasis (ALNM).Forty-seven breast cancer patients with ALNM who underwent surgery at Okayama University Hospital from 2002 to 2008 were enrolled. We retrospectively evaluated the levels of ALDH1 and transcription factors, such as Snail, Slug and Twist, in both primary and metastatic lesions by immunohistochemistry.In primary lesions, the positive rate of ALDH1, Snail, Slug and Twist was 19, 49, 40 and 26%, respectively. In lymph nodes, that of ALDH1, Snail, Slug and Twist was 21, 32, 13 and 23%, respectively. The expression of ALDH1 or transcription factors alone was not significantly associated with a poor prognosis. However, co-expression of ALDH1 and Slug in primary lesions was associated with a shorter DFS (P = 0.009).The evaluation of the co-expression of ALDH1 and transcription factors in primary lesions may be useful in prognosis of node-positive breast cancers.