SG compression therapy is effective for reducing nab-PTX-induced peripheral neuropathy. The nab-PTX exposure to the peripheral nerve may be decreased because the SG decreases microvascular flow to the fingertip.

The genetic and clinical characteristics of breast tumors with germline variants, including their association with biallelic inactivation through loss-of-heterozygosity (LOH) and second somatic mutations, remain elusive. We analyzed germline variants of 11 breast cancer susceptibility genes for 1,995 Japanese breast cancer patients, and identified 101 (5.1%) pathogenic variants, including 62 BRCA2 and 15 BRCA1 mutations. Genetic analysis of 64 BRCA1/2-mutated tumors including TCGA dataset tumors, revealed an association of biallelic inactivation with more extensive deletions, copy neutral LOH, gain with LOH and younger onset. Strikingly, TP53 and RB1 mutations were frequently observed in BRCA1- (94%) and BRCA2- (9.7%) mutated tumors with biallelic inactivation. Inactivation of TP53 and RB1 together with BRCA1 and BRCA2, respectively, involved LOH of chromosomes 17 and 13. Notably, BRCA1/2 tumors without biallelic inactivation were indistinguishable from those without germline variants. Our study highlights the heterogeneity and unique clonal selection pattern in breast cancers with germline variants.

The CLEOPATRA trial reported the survival benefit of pertuzumab with trastuzumab plus docetaxel in HER2-positive metastatic breast cancer patients. However, there are a few case reports concerning the effects of a pertuzumab-containing regimen on brain metastases. A 55-year-old woman, who underwent curative surgery for breast cancer after neoadjuvant chemotherapy 5 years previously, developed repeated solitary brain metastasis in her right occipital lobe. Whole brain radiation therapy, stereotactic radiosurgery and 3 times of surgical resection were performed. Lapatinib and capecitabine plus tamoxifen were administered. The metastasis recurred in the stump of the previous surgery. Pertuzumab with trastuzumab plus docetaxel was initiated as second-line chemotherapy. A complete response of the brain metastasis was achieved, which persisted for 5 months. Pertuzumab with trastuzumab plus docetaxel was effective in reducing the brain metastases from breast cancer. Further studies are warranted to confirm the effect of this regimen on brain metastases.

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Predicting pathogenic germline variants (PGVs) in breast cancer patients is important for selecting optimal therapeutics and implementing risk reduction strategies. However, PGV risk factors and the performance of prediction methods in the Japanese population remain unclear. We investigated clinicopathological risk factors using the Tyrer‐Cuzick (TC) breast cancer risk evaluation tool to predict BRCA PGVs in unselected Japanese breast cancer patients (n = 1,995). Eleven breast cancer susceptibility genes were analyzed using target‐capture sequencing in a previous study; the PGV prevalence in BRCA1, BRCA2, and PALB2 was 0.75%, 3.1%, and 0.45%, respectively. Significant associations were found between the presence of BRCA PGVs and early disease onset, number of familial cancer cases (up to third‐degree relatives), triple‐negative breast cancer patients under the age of 60, and ovarian cancer history (all P < .0001). In total, 816 patients (40.9%) satisfied the National Comprehensive Cancer Network (NCCN) guidelines for recommending multigene testing. The sensitivity and specificity of the NCCN criteria for discriminating PGV carriers from noncarriers were 71.3% and 60.7%, respectively. The TC model showed good discrimination for predicting BRCA PGVs (area under the curve, 0.75; 95% confidence interval, 0.69‐0.81). Furthermore, use of the TC model with an optimized cutoff of TC score ≥0.16% in addition to the NCCN guidelines improved the predictive efficiency for high‐risk groups (sensitivity, 77.2%; specificity, 54.8%; about 11 genes). Given the influence of ethnic differences on prediction, we consider that further studies are warranted to elucidate the role of environmental and genetic factors for realizing precise prediction.

PURPOSE: Chemotherapy-induced peripheral neuropathy (CIPN) is an adverse effect of many commonly used chemotherapeutic agents, including taxanes. However, there is currently no established effective prophylactic management for CIPN. Thus, we investigated the efficacy of using surgical glove (SG) compression therapy to prevent nanoparticle albumin-bound-paclitaxel (nab-PTX)-induced peripheral neuropathy. PATIENTS AND METHODS: Patients with primary and recurrent breast cancer who received 260 mg/m2 of nab-PTX were eligible for this case-control study. The patients wore two SGs of the same size, that is, one size smaller than the size that fit, on their dominant hand for 90 minutes. They did not wear SGs on the non-dominant hand, which served as the control hand. Peripheral neuropathy was evaluated at each treatment cycle using Common Terminology Criteria for Adverse Events (CTCAE) version 4.0 and the Patient Neurotoxicity Questionnaire (PNQ). The temperatures of each fingertip of the compression SG-protected and control hands were measured by using thermography. RESULTS: Between August 2013 and January 2016, 43 patients were enrolled, and 42 were evaluated. As shown in Table 1, the overall occurrence of ≥grade 2 sensory and motor peripheral neuropathy according to the CTCAE was significantly lower in the SG-protected hands than in the control hands (76.1% vs. 21.4% and 57.1% vs. 26.2%, respectively, p &lt; 0.0001). The PNQ results showed that the incidence of ≥grade 4 neuropathy was significantly higher in the control hands than in the SG-protected hands in terms of both sensory and motor neurotoxicity (p &lt; 0.0001, Table 2). As the treatment cycles of nab-PTX increased, the mean CTCAE and PNQ grades of the control hands gradually increased. However, the SG-protected hands maintained significantly lower mean grades than the control hands over time (p &lt; 0.0001). No patients withdrew from this study because they could not tolerate the compression from the SGs. The mean temperature of each fingertip significantly decreased (1.42–2.60 °C) in the SG-protected hands compared to in the control hands. CONCLUSIONS: SG compression therapy appears effective for reducing nab-PTX-induced peripheral neuropathy. The nab-PTX exposure to the peripheral nerve may be decreased because the SG decreases microvascular flow to the fingertip. Table 1: Comparison of the overall occurrences of the different grades of peripheral neuropathy according to CTCAE version 4.0 between the compression surgical glove-protected hands and control handsCTCAE v.4.0SensoryMotorGradeSurgical GloveControlSurgical GloveControl012418712161311292411163080840000 Table 2: Changes in the overall occurrence of the Patient Neurotoxicity Questionnaire (PNQ) grade with surgical glove compression therapyPNQSensoryMotorGradeSurgical gloveControlSurgical gloveControl194209223512113717912431611050000 Citation Format: Tsuyuki S, Senda N, Kanng Y, Yamaguchi A, Yoshibayashi H, Kikawa Y, Katakami N, Kato H, Hashimoto T, Okuno T, Yamauchi A, Inamoto T. Efficacy of compression therapy using surgical gloves for nanoparticle albumin-bound-paclitaxel-induced peripheral neuropathy: A phase II multicenter study by the Kamigata breast cancer study group [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 PD4-08.

Metastasis inhibition may improve survival of breast cancer patients. Our previous study revealed that a transcription factor SALL4 promotes cell migration for metastasis through up-regulation of integrin α6β1 in metastatic basal-like breast cancer cells. In these cells, integrin α6β1 modulates Rho GTPase activity, which enhances focal adhesion dynamics for cell migration. We therefore focused on integrin α6 as a therapeutic target for metastasis. We investigated the expression level of integrin α6 in breast cancer cell lines and a tissue microarray of breast cancer patients. In both experiments, we observed higher integrin α6 expression in basal-like breast cancer cells than in luminal ones. We performed shRNA-mediated integrin α6 knockdown in basal-like breast cancer cells and conducted Boyden chamber assays. In the results, reduced cell migration was observed in integrin α6 knocked-down cells. Reciprocally, we introduced integrin α6 overexpression in low-migratory luminal breast cancer cell lines and observed increased cell migration. These results indicate that integrin α6 promotes cell migration in breast cancer cells. To identify the functional residue of integrin α6, we analyzed its amino acid sequence by in silico analyses. First, we extracted integrin α6 specific residues in integrin α family in the human genome. Then, we compared integrin α6 sequences among vertebrates. In the result, we obtained an integrin α6-specific and vertebrate-conserved sequence, Asp-358, as a candidate for the functional residue. To inhibit integrin α6 function, we designed an 8-amino acid peptide with the sequence around Asp-358. Basal-like breast cancer cells treated with the peptide showed reduced cell migration in a dose-dependent manner. The peptide did not reduce cell migration in integrin α6 knocked-down cells, suggesting that the peptide inhibits integrin α6 function. To determine whether the peptide inhibits metastasis, we performed zebrafish metastasis assays, and observed reduced metastasis rate in the peptide-treated group. These results indicate that the peptide inhibits metastasis through reduction in cell migration. To understand the effect of the peptide, we performed chemical cross-liking assay in a basal-like breast cancer cell line. Protein samples from the cells treated with a cross-linker showed bands of integrin α6 complexes, and the intensities of these bands were reduced in the peptide-treated group. Moreover, we immunostained cells with an antibody for focal adhesion marker, phospho-paxillin, because integrins regulates focal adhesion formation for cell migration. In the results, the peptide reduced the number of focal adhesions. These observations indicate that the peptide inhibits integrin α6 function. In the future, our findings may contribute to development of a metastasis inhibition therapy. Citation Format: Itou J, Tanaka S, Senda N, Iida A, Sehara-Fujisawa A, Sato F, Toi M. A peptide with the conserved amino acid residue of integrin α6 inhibits metastasis through disruption of complex formation in breast cancer cells [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-01-11.

Background: Breast cancer risk models are used to predict the risk of carrying a variant, for one of the most common breast cancer susceptibility genes such as BRCA1 and BRCA2, and the lifetime risk of developing breast cancer. The prediction of harboring a germline variant of the BRCA gene and the development of breast or ovarian cancer over time affects the decision-making for undergoing genetic testing and screening using imaging techniques as the common practice. For instance, the American Cancer Society and the National Comprehensive Cancer Network (NCCN) recommends screening using MRI in women with 20% or greater lifetime risk of having breast cancer. We aimed to investigate the prediction of these risks in Japanese women, particularly on the relationship between the presence of pathogenic germline variants and breast cancer susceptibility genes, using a cohort of 1016 primary breast cancer patients. Patients and Methods: We analyzed a cohort of Japanese patients with primary breast cancer who were treated at the Kyoto University Hospital and the related institutions or hospitals from the period of 2011 to 2016. The germline variants were examined for a set of 13 breast cancer susceptibility genes, using targeted-capture sequencing of pooled DNA, and it was found that 66 out of 1016 patients had pathogenic variants. These included 11 functionally well-established genes (BRCA1, BRCA2, TP53, PTEN, CDH1, STK11, NF1, PALB2, ATM, CHEK2, and NBN) and two additional genes (BARD1 and BRIP1), which are recommended for the screening of high-risk patients with hereditary breast cancer in the NCCN guidelines. Using this cohort, we studied the association of the calculated risk of carrying a germline variant of BRCA1/ BRCA2, using the Tyrer-Cuzick model Breast Cancer Risk Evaluation Tool, within the laboratory germline test results. Results: Pathogenic germline variants of BRCA1/ BRCA2 were carried by 54 (5.3%) out of the 1016 patients (12 cases of BRCA1 and 42 cases of BRCA2). According to the NCCN guidelines, which focus on Genetic/ Familial High-Risk Assessment: Breast and Ovarian, it was found that 500 out of 1016 (49.2%)patients were categorized for considering germline testing. In fact, 38 (7.6%) of the 500 patients, harbored a pathogenic germline variant of BRCA1/ BRCA2. In the remaining 516 patients, 16 (3.1%) harbored the pathogenic germline variant of BRCA1/ BRCA2. The predictive risks of the Tyrer-Cuzick model Breast Cancer Risk Evaluation Tool were recorded as follows: Area under the ROC curve, BRCA1 (area 0.750, 95% CI- 0.581-0.919), BRCA2 (area 0.741, 95% CI- 0.661-0.820), BRCA1 or BRCA2 (Area 0.749, 95% CI: 0.675-0.822), suggesting that the Tyrer-Cuzick model may be useful for the Japanese population. In the mammography breast density analysis, 484 patients showed almost entirely fat or scattered fibroglandular breast tissue, and 362 cases had heterogeneous or extreme fibroglandular breast tissue. In this study, the correlations of breast tissue density with age and breast or ovarian cancer familial history have been reported in greater detail. Discussion and Conclusions: In a retrospective cohort of 1016 Japanese patients with primary breast cancer, 5.3% had pathogenic germline variants of BRCA1/ BRCA2. In a group recommended by NCCN guidelines for considering genetic testing, the BRCA1/ BRCA2 variant rate was 7.6%. Predictive risks calculated by the Tyrer-Cuzick model similar with the known data. Further data are reported. Citation Format: Noriko Senda, Nobuko Kawaguchi-Sakita, Masahiro Kawashima, Yukiko Inagaki-Kawata, Kenichi Yoshida, Tomomi Nishimura, Masahiro Takada, Eiji Suzuki, Yuki Kataoka, Fumiaki Sato, Yoshiaki Matsumoto, Masae Torii, Hiroshi Yoshibayashi, Kazuhiro Yamagami, Shigeru Tsuyuki, Akira Yamauchi, Nobuhiko Shinkura, Hironori Kato, Yoshio Moriguchi, Ryuji Okamura, Norimichi Kan, Hirofumi Suwa, Shingo Sakata, Susumu Mashima, Fumiaki Yotsumoto, Tsuyoshi Tachibana, Mitsuru Tanaka, Takashi Inamoto, Masahiro Sugimoto, Seishi Ogawa, Masakazu Toi. Relationship between predicted risks of carrying breast cancer susceptibility genes and the presence of germline variants in Japanese patients with primary breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-10-12.