Rapid diagnosis of lymph node metastasis in breast cancer using a new fluorescent method with γ-glutamyl hydroxymethyl rhodamine green

Association between serum γ-glutamyl transferase and advanced colorectal adenoma among inpatients: a case-control study

Emerging evidence suggests a link between γ-glutamyl transferase (GGT) and various malignancies. However, the relationship between GGT and advanced colorectal adenoma, a critical precursor to colorectal cancer, remains unclear. This study aimed to elucidate this relationship. We conducted a single-center retrospective study from April 2015 to June 2022, enrolling 3534 inpatients including 525 cases and 3009 controls. Data were extracted from the electronic medical records, encompassing clinicodemographic characteristics, co-morbidities, and several blood biochemical indicators. Utilizing logistic regression and curve fitting, we explored the relationship between GGT and advanced colorectal adenoma. After adjustment for confounding factors, we found that for each 20-unit increase in GGT, the risk of advanced colorectal adenoma increased by 6% (OR= 1.06 [1.01-1.12]). Moreover, individuals with high GGT levels (≥50 U/L) had a 61% higher risk of advanced colorectal adenoma compared to those with low GGT levels (<50 U/L) (OR=1.61 [1.13-2.31]). Subgroup analysis demonstrated the robustness of these findings across subjects with different characteristics. High GGT levels were associated with higher odds of advanced colorectal adenoma. Our findings suggest that elevated GGT levels may serve as a potential diagnostic marker for advanced colorectal adenoma, providing new insights into its screening strategies.

Real-Time Fluorescence Imaging to Identify Cholangiocarcinoma in the Extrahepatic Biliary Tree Using an Enzyme-Activatable Probe

Introduction

Complete resection is the only possible treatment for cholangiocarcinoma in the extrahepatic biliary tree (eCCA), although current imaging modalities are limited in their ability to accurately diagnose longitudinal spread. We aimed to develop fluorescence imaging techniques for real-time identification of eCCA using an enzyme-activatable probe, which emits fluorescence immediately after activation by a cancer-specific enzyme.

Methods

Using lysates and small tissue fragments collected from surgically resected specimens, we selected the most specific probe for eCCA from among 800 enzyme-activatable probes. The selected probe was directly sprayed onto resected specimens and fluorescence images were acquired; these images were evaluated for diagnostic accuracy. We also comprehensively searched for enzymes that could activate the probe, then compared their expression levels in cancer and non-cancer tissues.

Results

Analyses of 19 samples (four cancer lysates, seven non-cancer lysates, and eight bile samples) and 54 tissue fragments (13 cancer tissues and 41 non-cancer tissues) revealed that PM-2MeSiR was the most specific fluorophore for eCCA. Fluorescence images of 7 patients were obtained; these images enabled rapid identification of cancerous regions, which closely matched histopathology findings in 4 patients. Puromycin-sensitive aminopeptidase was identified as the enzyme that might activate the probe, and its expression was upregulated in eCCA.

Conclusion

Fluorescence imaging with PM-2MeSiR, which may be activated by puromycin-sensitive aminopeptidase, yielded generally high accuracy. This technique may be useful for real-time identification of the spread of eCCA during surgery and endoscopic examinations.

Development of an intraoperative breast cancer margin assessment method using quantitative fluorescence measurements

Breast-conserving surgery has become the preferred treatment method for breast cancer. Surgical margin assessment is performed during surgery, as it can reduce local recurrence in the preserved breast. Development of reliable and lower-cost ex vivo cancer detection methods would offer several benefits for patient care. Here, a practical and quantitative evaluation method for the ex vivo fluorescent diagnosis of breast lesions was developed and confirmed through a three-step clinical study. Gamma-glutamyl-hydroxymethyl rhodamine green (gGlu-HMRG) has been reported to generate fluorescence in breast lesions. Using this probe, we constructed a reliable and reproducible procedure for the quantitative evaluation of fluorescence levels. We evaluated the reliability of the method by considering reproducibility, temperature sensitivity, and the effects of other clinicopathological factors. The results suggest that the fluorescence increase of gGlu-HMRG is a good indicator of the malignancy of breast lesions. However, the distributions overlapped. A 5 min reaction with this probe could be used to distinguish at least part of the normal breast tissue. This method did not affect the final pathological examination. In summary, our results indicate that the methods developed in this study may serve as a feasible intraoperative negative-margin assessment tool during breast-conserving surgery.

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.

Efficient methodology to develop tumor-imaging fluorescent probes based on screening with our newly constructed probe library for aminopeptidase/protease (380 probes) and clinical samples has been established.

Fast Segmentation of Metastatic Foci in H&E Whole-Slide Images for Breast Cancer Diagnosis

Breast cancer is the leading cause of death for women globally. In clinical practice, pathologists visually scan over enormous amounts of gigapixel microscopic tissue slide images, which is a tedious and challenging task. In breast cancer diagnosis, micro-metastases and especially isolated tumor cells are extremely difficult to detect and are easily neglected because tiny metastatic foci might be missed in visual examinations by medical doctors. However, the literature poorly explores the detection of isolated tumor cells, which could be recognized as a viable marker to determine the prognosis for T1NoMo breast cancer patients. To address these issues, we present a deep learning-based framework for efficient and robust lymph node metastasis segmentation in routinely used histopathological hematoxylin−eosin-stained (H−E) whole-slide images (WSI) in minutes, and a quantitative evaluation is conducted using 188 WSIs, containing 94 pairs of H−E-stained WSIs and immunohistochemical CK(AE1/AE3)-stained WSIs, which are used to produce a reliable and objective reference standard. The quantitative results demonstrate that the proposed method achieves 89.6% precision, 83.8% recall, 84.4% F1-score, and 74.9% mIoU, and that it performs significantly better than eight deep learning approaches, including two recently published models (v3_DCNN and Xception-65), and three variants of Deeplabv3+ with three different backbones, namely, U-Net, SegNet, and FCN, in precision, recall, F1-score, and mIoU (p<0.001). Importantly, the proposed system is shown to be capable of identifying tiny metastatic foci in challenging cases, for which there are high probabilities of misdiagnosis in visual inspection, while the baseline approaches tend to fail in detecting tiny metastatic foci. For computational time comparison, the proposed method takes 2.4 min for processing a WSI utilizing four NVIDIA Geforce GTX 1080Ti GPU cards and 9.6 min using a single NVIDIA Geforce GTX 1080Ti GPU card, and is notably faster than the baseline methods (4-times faster than U-Net and SegNet, 5-times faster than FCN, 2-times faster than the 3 different variants of Deeplabv3+, 1.4-times faster than v3_DCNN, and 41-times faster than Xception-65).

Significance of Lymph Node Metastasis in the Treatment of Gastric Cancer and Current Challenges in Determining the Extent of Metastasis

The stomach exhibits abundant lymphatic flow, and metastasis to lymph nodes is common. In the case of gastric cancer, there is a regularity to the spread of lymph node metastasis, and it does not easily metastasize outside the regional nodes. Furthermore, when its extent is limited, nodal metastasis of gastric cancer can be cured by appropriate lymph node dissection. Therefore, identifying and determining the extent of lymph node metastasis is important for ensuring accurate diagnosis and appropriate surgical treatment in patients with gastric cancer. However, precise detection of lymph node metastasis remains difficult. Most nodal metastases in gastric cancer are microscopic metastases, which often occur in small-sized lymph nodes, and are thus difficult to diagnose both preoperatively and intraoperatively. Preoperative nodal diagnoses are mainly made using computed tomography, although the specificity of this method is low because it is mainly based on the size of the lymph node. Furthermore, peripheral nodal metastases cannot be palpated intraoperatively, nodal harvesting of resected specimens remains difficult, and the number of lymph nodes detected vary greatly depending on the skill of the technician. Based on these findings, gastrectomy with prophylactic lymph node dissection is considered the standard surgical procedure for gastric cancer. In contrast, several groups have examined the value of sentinel node biopsy for accurately evaluating nodal metastasis in patients with early gastric cancer, reporting high sensitivity and accuracy. Sentinel node biopsy is also important for individualizing and optimizing the extent of uniform prophylactic lymph node dissection and determining whether patients are indicated for function-preserving curative gastrectomy, which is superior in preventing post-gastrectomy symptoms and maintaining dietary habits. Notably, advancements in surgical treatment for early gastric cancer are expected to result in individualized surgical strategies with sentinel node biopsy. Chemotherapy for advanced gastric cancer has also progressed, and conversion gastrectomy can now be performed after downstaging, even in cases previously regarded as inoperable. In this review, we discuss the importance of determining lymph node metastasis in the treatment of gastric cancer, the associated difficulties, and the need to investigate strategies that can improve the diagnosis of lymph node metastasis.

Rapid visualization of mammary gland tumor lesions of dogs using the enzyme-activated fluorogenic probe; γ-glutamyl hydroxymethyl rhodamine green

Since gamma-glutamyl transpeptidase (GGT) is highly and locally expressed in human breast cancer, a GGT-enzymatically activatable fluorescent probe, gamma-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG), has been developed to detect the human breast cancer area with high performance. In this study, GGT expression and the efficacy of gGlu-HMRG on visualization were investigated in canine mammary gland tumors (MGT). Seventeen non-fixed fresh-frozen MGT specimens and each peritumoral control tissue were utilized. The GGT mRNA levels were highly observed in the tumor specimens compared with the control. GGT immunostaining was mostly observed on the cell membrane and cytosol of the alveolar and duct mammary epithelium of MGT tissues. These signals were strongly positive in several cases while they were mild to not observed in other cases. When gGlu-HMRG solution was dropped to the non-fixed tissue pieces of MGT or control tissues, the fluorescence intensities (FIs) were measured using Maestro in-vivo imaging device. FIs in MGT tissues were significantly higher than each control tissue 20 min after treatment. Based on Youden index method said that the maximum sensitivity and specificity of FI was 82.4% and 82.4%. These findings suggest that GGT is highly expressed in several MGTs in dogs and gGlu-HMRG could visualize at least a part of MGT tissues in dogs. Nevertheless, it should be needed to assess the false-negative areas more carefully in canine than human cases.

Fluorescence Imaging Using Enzyme-Activatable Probes for Real-Time Identification of Pancreatic Cancer

Introduction

Radical resection is the only curative treatment for pancreatic cancer, which is a life-threatening disease. However, it is often not easy to accurately identify the extent of the tumor before and during surgery. Here we describe the development of a novel method to detect pancreatic tumors using a tumor-specific enzyme-activatable fluorescence probe.

Methods

Tumor and non-tumor lysate or small specimen collected from the resected specimen were selected to serve as the most appropriate fluorescence probe to distinguish cancer tissues from noncancerous tissues. The selected probe was sprayed onto the cut surface of the resected specimen of cancer tissue to acquire a fluorescence image. Next, we evaluated the ability of the probe to detect the tumor and calculated the tumor-to-background ratio (TBR) by comparing the fluorescence image with the pathological extent of the tumor. Finally, we searched for a tumor-specific enzyme that optimally activates the selected probe.

Results

Using a library comprising 309 unique fluorescence probes, we selected GP-HMRG as the most appropriate activatable fluorescence probe. We obtained eight fluorescence images of resected specimens, among which four approximated the pathological findings of the tumor, which achieved the highest TBR. Finally, dipeptidyl-peptidase IV (DPP-IV) or a DPP-IV-like enzyme was identified as the target enzyme.

Conclusion

This novel method may enable rapid and real-time visualization of pancreatic cancer through the enzymatic activities of cancer tissues.

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.

Use of autofluorescence and fluorescent probes as a potential diagnostic tool for oral cancer: A systematic review

INTRODUCTION

The prognosis of patients with Oral squamous cell carcinoma (OSCC) are directly related to the stage of development of the tumor at the time of diagnosis, but it is estimated an average delay in diagnosis of 2-5 months. New non-invasive techniques for the early diagnosis of OSCC are being developed, such as methodologies to detect spectral changes of tumor cells. We conducted a systematic review to analyze the potential use of autofluorescence and/or fluorescent probes for OSCC diagnosis.

MATERIAL AND METHODS

Four databases (PubMed, Scopus, Embase and Web of Science) were used as research sources. Protocol was registered with PROSPERO. It was included studies that evaluated tissue autofluorescence and/or used fluorescent probes as a method of diagnosing and/or treatment of oral cancer in humans.

RESULTS

Forty-five studies were selected for this systematic review, of which 28 dealt only with autofluorescence, 18 on fluorescent probes and 1 evaluated both methods. The VELscope® was the most used device for autofluorescence, exhibiting sensitivity (33%-100%) and specificity (12%-88.6%). 5-Aminolevulinic acid (5-ALA) was the most used fluorescent probe, exhibiting high sensitivity (90%-100%) and specificity (51.3%-96%). Hypericin, rhodamine 6 G, rhodamine 610, porphyrin and γ-glutamyl hydroxymethyl rhodamine green have also been reported.

CONCLUSION

Thus, the autofluorescence and fluorescent probes can provide an accurate diagnosis of oral cancer, assisting the dentist during daily clinical activity, but it is not yet possible to suggest that this method may replace histopathological examination.

A novel method for rapid detection of a Helicobacter pylori infection using a γ-glutamyltranspeptidase-activatable fluorescent probe

A γ-glutamyl hydroxymethyl rhodamine green probe (gGlu-HMRG) reacts with γ-glutamyltranspeptidase (GGT) and immediately produces fluorescence, is clinically applied for real-time cancers' visualization. Since Helicobacter pylori produces GGT, this study aimed to investigate whether gGlu-HMRG can be used to detect H. pylori infections. A wild-type H. pylori strain and the ggt gene-disrupted mutant were cultured and treated with gGlu-HMRG. This fluorescent probe assay was used to quantify GGT activity of H. pylori ex vivo using gastric biopsy specimens. The H. pylori diagnostic capabilities of the assay were determined from altered fluorescence intensity (FI) values at 5 min (FIV-5) and 15 minutes (FIV-15). Distinct fluorescence was identified in wild H. pylori strain, using gGlu-HMRG, whereas no fluorescence was observed in ggt gene-disrupted mutant strain. On ex vivo imaging of gGlu-HMRG, fluorescence intensity increased markedly with time in H. pylori-positive specimens; however, the H. pylori-negative specimens displayed a slight increase in FI. FIV-5 and FIV-15 differed significantly between H. pylori-positive and -negative specimens. FIV-15 differed significantly between H. pylori-positive and -eradicated group. This assay sensitivity and specificity were 75.0% and 83.3% in the antrum and 82.6% and 89.5% in the stomach body. GGT-activatable fluorescence probe is applicable for rapid diagnosis of H. pylori.

Rapid detection of papillary thyroid carcinoma by fluorescence imaging using a γ-glutamyltranspeptidase-specific probe: a pilot study

Background

Nodular lesions of the thyroid gland, including papillary thyroid carcinoma (PTC), may be difficult to diagnose by imaging, such as in ultrasonic echo testing, or by needle biopsy. Definitive diagnosis is made by pathological examination but takes several days. A more rapid and simple method to clarify whether thyroid nodular lesions are benign or malignant is needed. Fluorescence imaging with γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG) uses γ-glutamyltranspeptidase (GGT), a cell-surface enzyme, to hydrolyze the γ-glutamyl peptide and transfer the γ-glutamyl group. GGT is overexpressed in several cancers, such as breast, lung, and liver cancers. This imaging method is rapid and useful for detecting such cancers. In this study, we tried to develop a rapid fluorescence detection method for clinical samples of thyroid cancer, especially papillary carcinoma.

Methods

Fluorescence imaging with gGlu-HMRG was performed to detect PTC using 23 surgically resected clinical samples. A portable imaging device conveniently captured white-light images and fluorescence images with blue excitation light. Hematoxylin-eosin (HE) staining was used to evaluate which fluorescent regions coincided with cancer, and immunohistochemical examination was used to detect GGT expression.

Results

All 16 PTC samples exhibited fluorescence after topical application of gGlu-HMRG, whereas the normal sections of each sample showed no fluorescence. HE staining revealed that each fluorescent region corresponded to a region with carcinoma. The PTC samples also exhibited GGT expression, as confirmed by immunohistochemistry.

Conclusions

All PTC samples were detected by fluorescence imaging with gGlu-HMRG. Thus, fluorescence imaging with gGlu-HMRG is a rapid, simple, and powerful detection tool for PTC.

Sensitive in vivo Visualization of Breast Cancer Using Ratiometric Protease-activatable Fluorescent Imaging Agent, AVB-620

With the goal of improving intraoperative cancer visualization, we have developed AVB-620, a novel intravenously administered, in vivo fluorescent peptide dye conjugate that highlights malignant tissue and is optimized for human use. Matrix metalloproteinases (MMPs) hydrolyze AVB-620 triggering tissue retention and a ratiometric fluorescence color change which is visualized using camera systems capable of imaging fluorescence and white light simultaneously. AVB-620 imaging visualizes primary tumors and demonstrated high in vivo diagnostic sensitivity and specificity (both >95%) for identifying breast cancer metastases to lymph nodes in two immunocompetent syngeneic mouse models. It is well tolerated and single-dose toxicology studies in rats determined a no-observed-adverse-effect-level (NOAEL) at >110-fold above the imaging and estimated human dose. Protease specificity and hydrolysis kinetics were characterized and compared using recombinant MMPs. To understand the human translation potential, an in vitro diagnostic study was conducted to evaluate the ability of AVB-620 to differentiate human breast cancer tumor from healthy adjacent tissue. Patient tumor tissue and healthy adjacent breast tissue were homogenized, incubated with AVB-620, and fluorogenic responses were compared. Tumor tissue had 2-3 fold faster hydrolysis than matched healthy breast tissue; generating an assay sensitivity of 96% and specificity of 88%. AVB-620 has excellent sensitivity and specificity for identifying breast cancer in mouse and human tissue. Significant changes were made in the design of AVB-620 relative to previous ratiometric protease-activated agents. AVB-620 has pharmaceutical properties, fluorescence ratio dynamic range, usable diagnostic time window, a scalable synthesis, and a safety profile that have enabled it to advance into clinical evaluation in breast cancer patients.

Retrospective observational study about reducing the false negative rate of the sentinel lymph node biopsy: Never underestimate the effect of subjective factors

Reducing the false negative rate of sentinel lymph node biopsy (SLNB) for breast cancer patients has always been a focus of clinical research. We aimed to map the sentinel lymph nodes (SLNs) in detail, and analyze the factors related to SLNs located at locations that are often ignored by surgeons, to reduce the rate of false negatives from SLNB. A retrospective analysis involving 545 breast cancer patients who underwent SLNB in west China hospital between August 2010 and February 2016 was performed. Blue dye, radioisotope, or combined methods were used for tracing SLNs. Using blue dye, radioisotope, and a combination of blue dye and radioisotope successfully traced SLNs in 479, 507, and 525 patients, the detection rate was 88.2%, 93.9%, and 97.4%, respectively. Among the 1559 detected SLNs, 139 (9.6%) were located at the latissimus dorsi lateral margin, and 108 (6.9%) were located at level 2. Subcutaneous injection of radioisotope (P = .004) and intradermal injection of blue dye (P = .002) were independent factors associated with SLNs distributed at level 2 and the latissimus dorsi lateral margin, respectively. It was noteworthy that 2 of 7 patients had skipping metastasis in level 2, so subcutaneous injection of the isotope is strongly recommended for tracing SLNs distributed in level 2 because of the possibility of skipping metastasis. Though intradermal injection of blue dye was superior methods for tracing SLNs located at the latissimus dorsi lateral margin, we surprisingly found those patients with metastasis to the latissimus dorsi lateral margin nodes also could have metastasis to level 1 (expect for the latissimus dorsi lateral margin) nodes, it seemed that maybe there is no need to excise SLNs at the latissimus dorsi lateral margin in SLNB, whether such nodes should be regarded as useful for SLNB still needs to be determined by further large, multicenter clinical studies.

Intraoperative imaging of hepatic cancers using γ-glutamyltranspeptidase-specific fluorophore enabling real-time identification and estimation of recurrence

γ-Glutamyltranspeptidase (GGT) is upregulated in a variety of human cancers including primary and secondary hepatic tumors. This motivated us to use γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG), a novel fluorophore emitting light at around 520 nm following enzymatic reaction with GGT, as a tool for the intraoperative identification of hepatic tumors. gGlu-HMRG was topically applied to 103 freshly resected hepatic specimens. Fluorescence imaging using gGlu-HMRG identified hepatic tumors with the sensitivity/specificity of 48%/96% for hepatocellular carcinoma, 100%/100% for intrahepatic cholangiocarcinoma, and 87%/100% for colorectal liver metastasis. High gGlu-HMRG fluorescence intensity was positively associated with the incidence of microscopic vascular invasion in HCC and the risk of early postoperative recurrence in CRLM. These results suggest that gGlu-HMRG imaging could not only be a useful intraoperative navigation tool but also provide information related to postoperative disease recurrence.

Efficacious fluorescence turn-on probe for high-contrast imaging of human cells overexpressing quinone reductase activity

A turn-on substrate probe is activated by an oxidoreductase, offering fluorescence images of cancer cells with unprecedented positive signal-to-negative background ratios.