Lack of impact of the ALDH2 rs671 variant on breast cancer development in Japanese BRCA1/2-mutation carriers.

The aldehyde degrading function of the ALDH2 enzyme is impaired by Glu504Lys polymorphisms (rs671, termed A allele), which causes alcohol flushing in east Asians, and elevates the risk of esophageal cancer among habitual drinkers. Recent studies suggested that the ALDH2 variant may lead to higher levels of DNA damage caused by endogenously generated aldehydes. This can be a threat to genome stability and/or cell viability in a synthetic manner in DNA repair-defective settings such as Fanconi anemia (FA). FA is an inherited bone marrow failure syndrome caused by defects in any one of so far identified 22 FANC genes including hereditary breast and ovarian cancer (HBOC) genes BRCA1 and BRCA2. We have previously reported that the progression of FA phenotypes is accelerated with the ALDH2 rs671 genotype. Individuals with HBOC are heterozygously mutated in either BRCA1 or BRCA2, and the cancer-initiating cells in these patients usually undergo loss of the wild-type BRCA1/2 allele, leading to homologous recombination defects. Therefore, we hypothesized that the ALDH2 genotypes may impact breast cancer development in BRCA1/2 mutant carriers. We genotyped ALDH2 in 103 HBOC patients recruited from multiple cancer centers in Japan. However, we were not able to detect any significant differences in clinical stages, histopathological classification, or age at clinical diagnosis across the ALDH2 genotypes. Unlike the effects in hematopoietic cells of FA, our current data suggest that there is no impact of the loss of ALDH2 function in cancer initiation and development in breast epithelium of HBOC patients.

Optimization of prediction methods for risk assessment of pathogenic germline variants in the Japanese population.

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.

Genetic and clinical landscape of breast cancers with germline BRCA1/2 variants.

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.

In silico analysis-based identification of the target residue of integrin α6 for metastasis inhibition of basal-like breast cancer.

Metastasis causes death in breast cancer patients. To inhibit breast cancer metastasis, we focused on integrin α6, a membrane protein that contributes to cell migration and metastasis. According to in silico analysis, we identified Asp-358 as an integrin α6-specific vertebrate-conserved residue and consequently as a potential therapeutic target. Because Asp-358 is located on the surface of the ß propeller domain that interacts with other molecules for integrin α6 function, we hypothesized that a peptide with the sequence around Asp-358 competitively inhibits integrin α6 complex formation. We treated basal-like breast cancer cells with the peptide and observed reductions in cell migration and metastasis. The result of the immunoprecipitation assay showed that the peptide inhibited integrin α6 complex formation. Our immunofluorescence for phosphorylated paxillin, a marker of integrin-regulated focal adhesion, showed that the peptide reduced the number of focal adhesions. These results indicate that the peptide inhibits integrin α6 function. This study identified the functional residue of integrin α6 and designed the inhibitory peptide. For breast cancer patients, metastasis inhibition therapy may be developed in the future based on this study.

Evaluation of the effect of compression therapy using surgical gloves on nanoparticle albumin-bound paclitaxel-induced peripheral neuropathy: a phase II multicenter study by the Kamigata Breast Cancer Study Group.

PURPOSE: To investigate 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. Patients wore two SGs of the same size, i.e., one size smaller than the size that fit their dominant hand, for only 90 min. They did not wear two 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. The temperature of each fingertip of the compression SG-protected hand and control hand was measured using thermography. RESULTS: Between August 2013 and January 2016, 43 patients were enrolled and 42 were evaluated. The occurrence rates of CTCAE grade 2 or higher sensory and motor peripheral neuropathies were significantly lower for SG-protected hands than for control hands (sensory neuropathy 21.4 vs. 76.1 %; motor neuropathy 26.2 vs. 57.1 %). No patients withdrew from this study because they could not tolerate the compression from the SGs. SG compression therapy significantly decreased the temperature of each fingertip by 1.6-2.2 °C as compared with the temperature before chemotherapy (p < 0.0001). CONCLUSIONS: 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.

Pertuzumab, trastuzumab and docetaxel reduced the recurrence of brain metastasis from breast cancer: a case report.

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.