Poor Treatment Outcomes with Second-Line Chemotherapy in Advanced Synovial Sarcoma.

INTRODUCTION: Synovial sarcoma (SS) predominantly affects adolescents and young adults. Doxorubicin with or without ifosfamide therapy is the standard first-line treatment for unresectable or metastatic SS. However, there is no standard second-line chemotherapy regimen. The purpose of the current study was to evaluate the outcomes of second-line chemotherapy for patients with SS. METHODS: We retrospectively evaluated the outcomes of 61 patients with unresectable or metastatic SS who had received first-line chemotherapy at our institution between 1997 and 2017. Patients who received second-line chemotherapy were included in the analysis. Outcomes of the chemotherapy were evaluated. RESULTS: Among the 61 patients treated with first-line chemotherapy, we identified 32 patients who received second-line chemotherapy. Most patients (62.5%) were under 40 years of age. Regarding second-line chemotherapy regimens, 6 (18.8%) patients were treated with doxorubicin with/without ifosfamide, 6 (18.8%) with ifosfamide and etoposide, 4 (12.5%) with docetaxel and gemcitabine, 5 (15.6%) with pazopanib, 2 (6.2%) with trabectedin, and 1 (3.1%) with eribulin. The overall response rate according to the Response Evaluation Criteria in Solid Tumors for all patients was 9.4%. Eleven patients (34.3%) achieved disease-control for >6 months. The median follow-up duration was 15.2 months. The 1-year progression-free and overall survival rates were 33.1% and 67.1%, respectively. CONCLUSION: Our exploratory study revealed that the response rate of second-line chemotherapy regimens for patients with SS was 9.4%. Therefore, there is an urgent need to develop more active therapeutic regimens for SSs.

Improving Intramolecular Hopping Charge Transport via Periodical Segmentation of π-Conjugation in a Molecule.

The development of several-nanometer-scale π-conjugated systems for efficient intramolecular hopping charge transport remains a significant challenge. To construct localized electronic structures at the same energy in a molecule, a series of oligothiophenes, with lengths up to 10 nm and periodically twisted structures, was synthesized. Single-molecule conductance measurements of the twisted molecules revealed resistances lower than those of planar oligothiophenes. This study provides a rational molecular design to improve the intramolecular hopping charge transport in materials.

Single-Molecule Conductance of a π-Hybridized Tripodal Anchor while Maintaining Electronic Communication.

Direct hybridization between the π-orbital of a conjugated molecule and metal electrodes is recognized as a new anchoring strategy to enhance the electrical conductance of single-molecule junctions. The anchor is expected to maintain direct hybridization between the conjugated molecule and the metal electrodes, and control the orientation of the molecule against the metal electrodes. However, fulfilling both requirements is difficult because multipodal anchors aiming at a robust contact with the electrodes often break the π-conjugation, thereby resulting in an inefficient carrier transport. Herein, a new tripodal anchor framework-a 7,7-diphenyl-7H-benzo[6,7]indeno[1,2-b]thiophene (PBIT) derivative-is developed. In this framework, π-conjugation is maintained in the molecular junction, and the tripodal structure makes the molecule stand upright on the metal electrode. Molecular conductance is measured by the break junction technique. A vector-based classification and first-principles transport calculations determine the single-molecule conductance of the tripodal-anchoring structure. The conductance of the PBIT-based molecule is higher than that of the tripodal anchor having sp3 carbon atoms in the carrier transport pathway. These results demonstrate that extending the π-conjugation to the tripodal leg is an effective strategy for enhancing the conductivities of single-molecule junctions.

BRAF V600E mutation is a potential therapeutic target for a small subset of synovial sarcoma.

Synovial sarcoma (SS) is an aggressive tumor that most often affects the deep soft tissues in young adults. Intrathoracic SS is rare and is associated with poor outcome, highlighting the urgent need for a novel therapeutic strategy. In the process of clinical sequencing, we identified two patients with intrathoracic SS harboring the BRAF V600E mutation. The patients were women aged 32 and 23 years, and both presented with SS18-SSX2-positive monophasic SS in the thoracic cavity. BRAF V600E mutations were detected by next generation sequencing, and validated immunohistochemically by diffuse intense positivity to BRAF V600E mutation-specific antibodies. The phosphorylated ERK (pERK) immunohistochemistry result was also positive. One patient received a combination therapy of dabrafenib and trametinib, which led to tumor shrinkage. However, the tumor growth progressed 7.5 months later with an additional NRAS Q61K mutation. Immunohistochemical screening of 67 archival SS tumor samples failed to identify additional samples with BRAF V600E mutation. However, 32% of BRAF V600E-negative cases was positive for pERK, and one of the six tumors showing the highest pERK expression harbored an FGFR2-activating mutation. This is the first report of targetable BRAF mutation in a small subset of SS. Our study suggests involvement of the mitogen-activated protein kinase pathway and the potential clinical implication of BRAF mutation screening in SS.

[Ifosfamide and Paclitaxel for Recurrent or Metastatic Uterine Carcinosarcoma].

AIM: This study aimed to retrospectively evaluate the efficacy and safety of ifosfamide plus paclitaxel(IT)in Japanese patients with recurrent or metastatic uterine carcinosarcoma. METHODS: This study included 15 patients who received IT(ifosfamide [1.6 g/m / 2 on days 1-3]and paclitaxel[135mg/m2 on day 1]every 3 weeks)for recurrent or metastatic uterine carcinosarcoma. RESULTS: The overall response rate was 38.4%, and the disease control rate was 92.3%. The median progression- free survival was 7.0 months, and the median overall survival was 9.0 months after initiation of IT therapy. The most common hematological adverse event was Grade 1-2 neutropenia. Peripheral neuropathy of Grade 1 or 2 was observed in 33.3% of cases. There was no treatment-related death. CONCLUSION: IT therapy showed good efficacy and tolerability in Japanese patients with recurrent or metastatic uterine carcinosarcoma.

Colorless Near-Infrared Absorbing Dyes Based on B-N Fused Donor-Acceptor-Donor π-Conjugated Molecules for Organic Phototransistors.

The introduction of a colorless function to organic electronic devices allows responses to light in the near-infrared (NIR) region and is expected to broaden the applications of these devices. However, the development of a colorless NIR dye remains a challenge due to the lack of a rational molecular design for controlling electronic transitions. In this study, to suppress the π-π* transitions in the visible region, polycyclic donor-acceptor-donor π-conjugated molecules with boron bridges (Py-FNTz-B and IP-FNTz-B) are designed and synthesized, which contain pyrrole or indenopyrrole as donor units with fluorinated naphthobisthiadiazole (FNTz) as an acceptor unit. The pyrrole end-capped Py-FNTz-B shows an absorption band in the NIR region without distinct visible-light absorption, which has led to the establishment of colorless characteristics. The indenopyrrole end-capped IP-FNTz-B shows a narrow optical energy gap of 0.87 eV in films. Time-resolved microwave conductance and field-effect transistors demonstrate the semiconducting characteristics of these molecules, and Py-FNTz-B-based devices function as NIR phototransistors. Theoretical analyses indicate that the combination of a polyene-like electronic structure with orbital symmetry is important to obtain NIR wavelength-selective absorption. This study suggests that a molecular design based on electronic structures can be effective in the development of colorless NIR-absorbing dyes for organic electronics.

Tetrazolo[1,5-a]pyridine-Containing π-Conjugated Systems: Synthesis, Properties, and Semiconducting Characteristics.

The incorporation of an electron-accepting unit into π-conjugated systems is an important approach to modulate the physical properties of such molecules. To investigate the potential of tetrazolo[1,5-a]pyridine as an electron-accepting unit, a series of diarylated tetrazolo[1,5-a]pyridine derivatives was synthesized by treating the corresponding diarylated pyridine N-oxide with diphenylphosphoryl azide. Thermogravimetric analyses of these molecules indicated that they possessed good thermal stability. The bithiophene-substituted tetrazolo[1,5-a]pyridine compound showed stable transistor characteristics under repeated bias conditions.

Response to Dabrafenib and Trametinib of a Patient with Metaplastic Breast Carcinoma Harboring a BRAF V600E Mutation.

BACKGROUND: Metaplastic breast carcinomas are rare and carry poor prognoses. They are also more aggressive than other breast cancers and are known for their resistance to chemotherapy. Prolonged treatment with dabrafenib and trametinib is a therapy for malignant melanoma that improves the progression-free survival and overall survival. Such molecular-targeted therapies are also being developed for cancers with BRAF mutation, a driver of malignant melanoma. Case Presentation. A 57-year-old woman with metaplastic breast cancer and chemotherapy-refractory massive pleural effusion. After contained anthracycline regimen failure, her breast cancer progressed to an advanced stage. We ordered next-generation sequencing- (NGS-) based tumor molecular profiling from core needle biopsy of the breast. The NGS report indicated the presence of a BRAF V600E mutation. After initiation of dabrafenib and trametinib, her symptom and the pleural effusion were decreased. The first assessment of CT scans showed a decreased pleural effusion and shrunken subcutaneous lesions. Approximately 2 weeks later, a new lesion appeared. She died from 12 weeks after initiation of dabrafenib and trametinib treatment. CONCLUSION: To the best of our knowledge, this is the first report of BRAF mutation breast cancer treated with dabrafenib and trametinib and it heralds the possibility of targeted therapy for rare breast cancers.

Highly Planar and Completely Insulated Oligothiophenes: Effects of π-Conjugation on Hopping Charge Transport.

Elucidating the nature of long-range intramolecular charge transport in π-conjugated molecules is of great importance for the development of organic electronic materials. However, the effects of the degree of π-conjugation on the hopping charge transport have not been experimentally explored so far owing to the lack of π-conjugated backbones with different conjugation degrees and several-nanometer lengths. Here we develop highly planar and completely insulated oligothiophenes between 0.85 and 9.64 nm in length. As compared to distorted oligothiophenes, single-molecule conductance measurements of the planar molecules show (i) a smaller activation energy and larger electrical conductance in the hopping transport regime and (ii) a shift in crossover between tunneling and hopping conduction toward a short molecular length. Theoretical calculations indicate that small reorganization energies and narrow energy gaps derived from the planar backbones result in these superior characteristics. This study reveals that the planarity of π-conjugation has significant advantages for hopping charge transport.