Rapid imaging of thymoma and thymic carcinoma with a fluorogenic probe targeting γ-glutamyltranspeptidase.

In recent years, thoracoscopic and robotic surgical procedures have increasingly replaced median sternotomy for thymoma and thymic carcinoma. In cases of partial thymectomy, the prognosis is greatly improved by ensuring a sufficient margin from the tumor, and therefore intraoperative fluorescent imaging of the tumor is especially valuable in thoracoscopic and robotic surgery, where tactile information is not available. γ-Glutamyl hydroxymethyl rhodamine green (gGlu-HMRG) has been applied for fluorescence imaging of some types of tumors in the resected tissues, and here we aimed to examine its validity for the imaging of thymoma and thymic carcinoma. 22 patients with thymoma or thymic carcinoma who underwent surgery between February 2013 and January 2021 were included in the study. Ex vivo imaging of specimens was performed, and the sensitivity and specificity of gGlu-HMRG were 77.3% and 100%, respectively. Immunohistochemistry (IHC) staining was performed to confirm expression of gGlu-HMRG's target enzyme, γ-glutamyltranspeptidase (GGT). IHC revealed high GGT expression in thymoma and thymic carcinoma in contrast to absent or low expression in normal thymic parenchyma and fat tissue. These results suggest the utility of gGlu-HMRG as a fluorescence probe for intraoperative visualization of thymomas and thymic carcinomas.

Rapid imaging of lung cancer using a red fluorescent probe to detect dipeptidyl peptidase 4 and puromycin-sensitive aminopeptidase activities.

Rapid identification of lung-cancer micro-lesions is becoming increasingly important to improve the outcome of surgery by accurately defining the tumor/normal tissue margins and detecting tiny tumors, especially for patients with low lung function and early-stage cancer. The purpose of this study is to select and validate the best red fluorescent probe for rapid diagnosis of lung cancer by screening a library of 400 red fluorescent probes based on 2-methyl silicon rhodamine (2MeSiR) as the fluorescent scaffold, as well as to identify the target enzymes that activate the selected probe, and to confirm their expression in cancer cells. The selected probe, glutamine-alanine-2-methyl silicon rhodamine (QA-2MeSiR), showed 96.3% sensitivity and 85.2% specificity for visualization of lung cancer in surgically resected specimens within 10 min. In order to further reduce the background fluorescence while retaining the same side-chain structure, we modified QA-2MeSiR to obtain glutamine-alanine-2-methoxy silicon rhodamine (QA-2OMeSiR). This probe rapidly visualized even borderline lesions. Dipeptidyl peptidase 4 and puromycin-sensitive aminopeptidase were identified as enzymes mediating the cleavage and consequent fluorescence activation of QA-2OMeSiR, and it was confirmed that both enzymes are expressed in lung cancer. QA-2OMeSiR is a promising candidate for clinical application.

Development of a fluorescent probe library enabling efficient screening of tumour-imaging probes based on discovery of biomarker enzymatic activities.

Fluorescent probes that can selectively detect tumour lesions have great potential for fluorescence imaging-guided surgery. Here, we established a library-based approach for efficient screening of probes for tumour-selective imaging based on discovery of biomarker enzymes. We constructed a combinatorial fluorescent probe library for aminopeptidases and proteases, which is composed of 380 probes with various substrate moieties. Using this probe library, we performed lysate-based in vitro screening and/or direct imaging-based ex vivo screening of freshly resected clinical specimens from lung or gastric cancer patients, and found promising probes for tumour-selective visualization. Further, we identified two target enzymes as novel biomarker enzymes for discriminating between tumour and non-tumour tissues. This library-based approach is expected to be an efficient tool to develop tumour-imaging probes and to discover new biomarker enzyme activities for various tumours and other diseases.

Rapid and Accurate Visualization of Breast Tumors with a Fluorescent Probe Targeting α-Mannosidase 2C1.

Accurate detection of breast tumors and discrimination of tumor from normal tissues during breast-conserving surgery are essential to reduce the risk of misdiagnosis or recurrence. However, existing probes show substantial background signals in normal breast tissues. In this study, we focus on glycosidase activities in breast tumors. We synthesized a series of 12 fluorescent probes and performed imaging-based evaluation on surgically resected human breast specimens. Among them, the α-mannosidase-reactive fluorescent probe HMRef-αMan detected breast cancer with 90% sensitivity and 100% specificity. We identified α-mannosidase 2C1 as the target enzyme and confirmed its overexpression in various breast tumors. We found that fibroadenoma, the most common benign breast lesion in young woman, tends to have higher α-mannosidase 2C1 activity than malignant cancer. Combined application of green-emitting HMRef-αMan and a red-emitting γ-glutamyltranspeptidase probe enabled efficient dual-color, dual-target optical discrimination of malignant and benign tumors.

Preoperative lung surface localization for pulmonary wedge resection: a single-center experience.

BACKGROUND: Preoperative lung surface localization is effective in sublobar resection for small lung nodules. However, the efficacy may vary depending on the underlying conditions of the lung and tumor, as well as the technique. This study aimed to evaluate the efficacy and limitations of preoperative lung surface localization for wedge resection by analyzing the outcomes of computed tomography (CT)-guided percutaneous marking and virtual-assisted lung mapping (VAL-MAP). METHODS: We investigated 215 patients who underwent curative wedge resection for malignant tumors using CT-guided localization or VAL-MAP from 1998 to 2018 in our institute. Each resected nodule was assessed for successful resection, which was defined as complete resection with adequate margins. RESULTS: One-hundred-and-nineteen patients with 153 nodules were included. The overall successful resection rate was 87.6%. The successful resection rate was significantly lower for nodules with intraoperative adhesion than those without intraoperative adhesion (75.0% vs. 90.1%; P=0.034), and for tumors requiring deep resection margins (>31 mm) than those requiring shallow margins (≤31 mm) (76.7% vs. 94.6%; P=0.002). Although the successful resection rate for nodules resected using CT-guided localization was significantly lower in cases with versus without intraoperative adhesion (54.5% vs. 86.7%; P=0.048), the successful resection rate for nodules resected using VAL-MAP was not influenced by the presence or absence of adhesion (85.7% vs. 93.4%; P=0.491). CONCLUSIONS: A requirement for deeper resection and the presence of intraoperative adhesion were limitations of preoperative lung surface localization for curative pulmonary wedge resection.

ɤ-glutamyl hydroxymethyl rhodamine green fluorescence as a prognostic indicator for lung cancer.

OBJECTIVE: ɤ-glutamyltranspeptidase is an enzyme expressed in various malignancies including lung cancer. It rapidly activates non-fluorescent ɤ-glutamyl hydroxymethyl rhodamine green to highly fluorescent hydroxymethyl rhodamine green. The resultant tumor fluorescence is therefore an indicator of cellular ɤ-glutamyltranspeptidase activity. We have explored the use of ɤ-glutamyl hydroxymethyl rhodamine green as an intraoperative imaging tool for visualizing cancers. Herein, we evaluated the potential of the tumor fluorescence as a postoperative prognostic indicator. METHODS: We included patients with non-small cell lung cancer who had undergone radical resection from 2012 to 2014 in the study. We assessed the fluorescence intensity of the resected tumor and normal lung tissue by ex vivo imaging using ɤ-glutamyl hydroxymethyl rhodamine green. RESULTS: Sixty-seven patients were eligible for the study (adenocarcinomas, n = 44; squamous cell carcinoma, n = 14; other histologies, n = 8). The pathological stages were I, II, III, and IV in 39, 15, 12, and 1 patient, respectively. Based on the fluorescence of the tumor tissue, the patients were divided into high fluorescence (n = 33) and low fluorescence (n = 34) groups. The 5-year overall survival rate was significantly higher in the high fluorescence group (72.7%) compared to the low fluorescence group (47.1%, P = 0.025). Similarly, pathological stage I patients of the high fluorescence group had higher 5-year overall survival (85.7% vs. 44.4%, P = 0.009) and recurrence-free survival (76.2% vs. 44.4% P = 0.044) rates compared to those of the low fluorescence group. CONCLUSIONS: ɤ-glutamyl hydroxymethyl rhodamine green fluorescence is a good postoperative prognostic indicator in patients with non-small cell lung cancer.

[A case of carcinomatous cardiac tamponade caused by breast cancer treated with instillation of paclitaxel and minocycline].

The patient was a 56-year-old woman who had undergone the Patey operation for left breast cancer when she was 45 years old. She had complained of dyspnea and shortness of breath at the time of exercise. Bilateral accumulation of pleural effusion and pericardial fluid was observed on chest radiographs and computed tomography(CT)scans. Under the diagnosis of cardiac tamponade, the patient was treated with pericardial drainage and local chemotherapy(intra-pericardial dosage of paclitaxel 45 mg and minocycline 100 mg)with the aim of preventing the accumulation of pericardial effusion. Subsequently, the pericardial effusion continued to disappear. The patient was treated with systemic chemotherapy. At the age of 58 years, she died of breast cancer. After treatment with pericardial drainage and local chemotherapy, she did not experience pericardial reaccumulation or cardiac tamponade. Thus, the method of local chemotherapy(intra-pericardial dosage of paclitaxel 45 mg and minocycline 100 mg)was considered effective.