Origin of chirality in transition-metal dichalcogenides

Chirality is a ubiquitous phenomenon in which a symmetry between left- and right-handed objects is broken, examples in nature ranging from subatomic particles and molecules to living organisms. In particle physics, the weak force is responsible for the symmetry breaking and parity violation in beta decay, but in condensed matter systems interactions that lead to chirality remain poorly understood. Here, we unravel the mechanism of chiral charge density wave formation in the transition-metal dichalcogenide 1T-TiSe2. Using representation analysis, we show that charge density modulations and ionic displacements, which transform as a continuous scalar field and a vector field on a discrete lattice, respectively, follow different irreducible representations of the space group, despite the fact that they propagate with the same wave-vectors and are strongly coupled to each other. This charge-lattice symmetry frustration is resolved by further breaking of all symmetries not common to both sectors through induced lattice distortions, thus leading to chirality. Our theory is verified using Raman spectroscopy and inelastic x-ray scattering, which reveal that all but translation symmetries are broken at a level not resolved by state-of-the-art diffraction techniques.Comment: 10 pages, 3 figures, 1 tabl

Prognostic Significance of HER2 Gene Amplification According to Stage of Breast Cancer

It is well known that the amplification of the HER2 gene is closely associated with poor prognosis of breast cancer. However, there is controversy about the clinical significance of HER2 according to lymph node status in breast cancer. The aim of this study was to identify the differences in the prognostic significance of HER2 gene amplification according to the stages of breast cancer. We prepared a tissue array for fluorescence in situ hybridization (FISH) with breast cancer specimens from the surgery in 1994 to 1999. Total 338 cases of breast cancer were enrolled and the median follow-up period was 6.3 yr. The detection rates of HER2 gene amplification were as follows: 10.3% in stage I, 22.3% in stage II, and 43.8% in stage III. On survival analyses HER2-positive groups showed worse prognosis in stage III of breast cancer, but not in stage I or II. Multivariate analyses with a Cox-regression model also revealed that HER2 amplification was an independent prognostic factor only in stage III breast cancer. Regarding HER2 gene amplification as a prognostic factor of breast cancer, the clinical significance of the gene was found to be confined to advanced breast cancer

Immunocytes as a Biocarrier to Delivery Therapeutic and Imaging Contrast Agents to Tumors

Radiotherapy for cancer treatment has been used for primary or adjuvant treatment in many types of cancer, and approximately half of all cancer patients are undergoing radiation. However, ionizing radiation exposure induces genetic alterations in cancer cells and results in recruitment of monocytes/macrophages by triggering signals released from these cells. Using this characteristic of monocytes/macrophages, we have attempted to develop a biocarrier loading radiosensitizing anticancer agents that can lead to enhance the therapeutic effect of radiation in cancer treatment. The aim of this study is to demonstrate the proof of this concept. THP-1 labeled with Qdot 800 or iron oxide (IO) effectively migrated into tumors of subcutaneous mouse model and increased recruitment after ionizing radiation. Functionalized liposomes carrying a radiosensitizing anticancer agent, doxorubicin, are successfully loaded in THP-1 (THP-1-LP-Dox) with reduced cytotoxicity, and THP-1-LP-Dox also was observed in tumors after intravenous administration. Here, we report that monocytes/macrophages as a biocarrier can be used as a selective tool for amplification of the therapeutic effects on radiotherapy for human cancer treatment

Transcriptional regulatory networks of tumor-associated macrophages that drive malignancy in mesenchymal glioblastoma.

BACKGROUND: Glioblastoma (GBM) is a complex disease with extensive molecular and transcriptional heterogeneity. GBM can be subcategorized into four distinct subtypes; tumors that shift towards the mesenchymal phenotype upon recurrence are generally associated with treatment resistance, unfavorable prognosis, and the infiltration of pro-tumorigenic macrophages. RESULTS: We explore the transcriptional regulatory networks of mesenchymal-associated tumor-associated macrophages (MA-TAMs), which drive the malignant phenotypic state of GBM, and identify macrophage receptor with collagenous structure (MARCO) as the most highly differentially expressed gene. MARCO CONCLUSIONS: Collectively, our study characterizes the global transcriptional profile of TAMs driving mesenchymal GBM pathogenesis, providing potential therapeutic targets for improving the effectiveness of GBM immunotherapy

Prevalence and detection of low-allele-fraction variants in clinical cancer samples

Accurate detection of genomic alterations using high-throughput sequencing is an essential component of precision cancer medicine. We characterize the variant allele fractions (VAFs) of somatic single nucleotide variants and indels across 5095 clinical samples profiled using a custom panel, CancerSCAN. Our results demonstrate that a significant fraction of clinically actionable variants have low VAFs, often due to low tumor purity and treatment-induced mutations. The percentages of mutations under 5% VAF across hotspots in EGFR, KRAS, PIK3CA, and BRAF are 16%, 11%, 12%, and 10%, respectively, with 24% for EGFR T790M and 17% for PIK3CA E545. For clinical relevance, we describe two patients for whom targeted therapy achieved remission despite low VAF mutations. We also characterize the read depths necessary to achieve sensitivity and specificity comparable to current laboratory assays. These results show that capturing low VAF mutations at hotspots by sufficient sequencing coverage and carefully tuned algorithms is imperative for a clinical assay