The Rab GTPase-binding protein EHBP1L1 and its interactors CD2AP/CIN85 negatively regulate the length of primary cilia via actin remodeling.

Primary cilia are organelles consisting of axonemal microtubules and plasma membranes, and they protrude from the cell surface to the extracellular region and function in signal sensing and transduction. The integrity of cilia, including the length and structure, is associated with signaling functions; however, factors involved in regulating the integrity of cilia have not been fully elucidated. Here, we showed that the Rab GTPase-binding protein EHBP1L1 and its newly identified interactors CD2AP and CIN85, known as adaptor proteins of actin regulators, are involved in ciliary length control. Immunofluorescence microscopy showed that EHBP1L1 and CD2AP/CIN85 are localized to the ciliary sheath. EHBP1L1 depletion caused mislocalization of CD2AP/CIN85, suggesting that CD2AP/CIN85 localization to the ciliary sheath is dependent on EHBP1L1. Additionally, we determined that EHBP1L1- and CD2AP/CIN85-depleted cells had elongated cilia. The aberrantly elongated cilia phenotype and the ciliary localization defect of CD2AP/CIN85 in EHBP1L1-depleted cells were rescued by the expression of WT EHBP1L1, although this was not observed in the CD2AP/CIN85-binding-deficient mutant, indicating that the EHBP1L1-CD2AP/CIN85 interaction is crucial for controlling ciliary length. Furthermore, EHBP1L1- and CD2AP/CIN85-depleted cells exhibited actin nucleation and branching defects around the ciliary base. Taken together, our data demonstrate that the EHBP1L1-CD2AP/CIN85 axis negatively regulates ciliary length via actin network remodeling around the basal body.

Identification of TEKTIN1-expressing multiciliated cells during spontaneous differentiation of non-human primate embryonic stem cells.

Tektins are a group of microtubule-stabilizing proteins necessary for cilia and flagella assembly. TEKTIN1 (TEKT1) is used as a sperm marker for monitoring germ cell differentiation in embryonic stem (ES) and induced pluripotent stem (iPS) cells. Although upregulation of TEKT1 has been reported during spontaneous differentiation of ES and iPS cells, it is unclear which cells express TEKT1. To identify TEKT1-expressing cells, we established an ES cell line derived from cynomolgus monkeys (Macaca fascicularis), which expresses Venus controlled by the TEKT1 promoter. Venus expression was detected at 5 weeks of differentiation on the surface of the embryoid body (EB), and it gradually increased with the concomitant formation of a leash-like structure at the EB periphery. Motile cilia were observed on the surface of the Venus-positive leash-like structure after 8 weeks of differentiation. The expression of cilia markers as well as TEKT1-5 and 9 + 2 microtubule structures, which are characteristic of motile cilia, were detected in Venus-positive cells. These results demonstrated that TEKT1-expressing cells are multiciliated epithelial-like cells that form a leash-like structure during the spontaneous differentiation of ES and iPS cells. These findings will provide a new research strategy for studying cilia biology, including ciliogenesis and ciliopathies.

New Diagnostic Modality Combining Mass Spectrometry and Machine Learning for the Discrimination of Malignant Intraductal Papillary Mucinous Neoplasms.

BACKGROUND: An intraductal papillary mucinous neoplasm (IPMN) is a pancreatic tumor with malignant potential. Although we anticipate a sensitive method to diagnose the malignant conversion of IPMN, an effective strategy has not yet been established. The combination of probe electrospray ionization-mass spectrometry (PESI-MS) and machine learning provides a promising solution for this purpose. METHODS: We prospectively analyzed 42 serum samples obtained from IPMN patients who underwent pancreatic resection between 2020 and 2021. Based on the postoperative pathological diagnosis, patients were classified into two groups: IPMN-low grade dysplasia (n = 17) and advanced-IPMN (n = 25). Serum samples were analyzed by PESI-MS, and the obtained mass spectral data were converted into continuous variables. These variables were used to discriminate advanced-IPMN from IPMN-low grade dysplasia by partial least square regression or support vector machine analysis. The areas under receiver operating characteristics curves were obtained to visualize the difference between the two groups. RESULTS: Partial least square regression successfully discriminated the two disease classes. From another standpoint, we selected 130 parameters from the entire dataset by PESI-MS, which were fed into the support vector machine. The diagnostic accuracy was 88.1%, and the area under the receiver operating characteristics curve was 0.924 by this method. Approximately 10 min were required to perform each method. CONCLUSION: PESI-MS combined with machine learning is an easy-to-use tool with the advantage of rapid on-site analysis. Here, we show the great potential of our system to diagnose the malignant conversion of IPMN, which would be a promising diagnostic tool in clinical settings.

Probe electrospray ionization mass spectrometry-based rapid diagnosis of liver tumors.

BACKGROUND AND AIM: Prompt differential diagnosis of liver tumors is clinically important and sometimes difficult. A new diagnostic device that combines probe electrospray ionization-mass spectrometry (PESI-MS) and machine learning may help provide the differential diagnosis of liver tumors. METHODS: We evaluated the diagnostic accuracy of this new PESI-MS device using tissues obtained and stored from previous surgically resected specimens. The following cancer tissues (with collection dates): hepatocellular carcinoma (HCC, 2016-2019), intrahepatic cholangiocellular carcinoma (ICC, 2014-2019), and colorectal liver metastasis (CRLM, 2014-2019) from patients who underwent hepatic resection were considered for use in this study. Non-cancerous liver tissues (NL) taken from CRLM cases were also incorporated into the analysis. Each mass spectrum provided by PESI-MS was tested using support vector machine, a type of machine learning, to evaluate the discriminatory ability of the device. RESULTS: In this study, we used samples from 91 of 139 patients with HCC, all 24 ICC samples, and 103 of 202 CRLM samples; 80 NL from CRLM cases were also used. Each mass spectrum was obtained by PESI-MS in a few minutes and was evaluated by machine learning. The sensitivity, specificity, and diagnostic accuracy of the PESI-MS device for discriminating HCC, ICC, and CRLM from among a mix of all three tumors and from NL were 98.9%, 98.1%, and 98.3%; 87.5%, 93.1%, and 92.6%; and 99.0%, 97.9%, and 98.3%, respectively. CONCLUSION: This study demonstrated that PESI-MS and machine learning could discriminate liver tumors accurately and rapidly.

Standardized statement for the ethical use of human cadaveric tissues in anatomy research papers: Recommendations from Anatomical Journal Editors-in-Chief.

Human cadaveric donors are essential for research in the anatomical sciences. However, many research papers in the anatomical sciences often omit a statement regarding the ethical use of the donor cadavers or, as no current standardized versions exist, use language that is extremely varied. To rectify this issue, 22 editors-in-chief of anatomical journals, representing 17 different countries, developed standardized and simplified language that can be used by authors of studies that use human cadaveric tissues. The goal of these editor recommendations is to standardize the writing approach by which the ethical use of cadaveric donors is acknowledged in anatomical studies that use donor human cadavers. Such sections in anatomical papers will help elevate our discipline and promote standardized language use in others non anatomy journals and also other media outlets that use cadaveric tissues.

A new rapid diagnostic system with ambient mass spectrometry and machine learning for colorectal liver metastasis.

BACKGROUND: Probe electrospray ionization-mass spectrometry (PESI-MS) can rapidly visualize mass spectra of small, surgically obtained tissue samples, and is a promising novel diagnostic tool when combined with machine learning which discriminates malignant spectrum patterns from others. The present study was performed to evaluate the utility of this device for rapid diagnosis of colorectal liver metastasis (CRLM). METHODS: A prospectively planned study using retrospectively obtained tissues was performed. In total, 103 CRLM samples and 80 non-cancer liver tissues cut from surgically extracted specimens were analyzed using PESI-MS. Mass spectra obtained by PESI-MS were classified into cancer or non-cancer groups by using logistic regression, a kind of machine learning. Next, to identify the exact molecules responsible for the difference between CRLM and non-cancerous tissues, we performed liquid chromatography-electrospray ionization-MS (LC-ESI-MS), which visualizes sample molecular composition in more detail. RESULTS: This diagnostic system distinguished CRLM from non-cancer liver parenchyma with an accuracy rate of 99.5%. The area under the receiver operating characteristic curve reached 0.9999. LC-ESI-MS analysis showed higher ion intensities of phosphatidylcholine and phosphatidylethanolamine in CRLM than in non-cancer liver parenchyma (P < 0.01, respectively). The proportion of phospholipids categorized as monounsaturated fatty acids was higher in CRLM (37.2%) than in non-cancer liver parenchyma (10.7%; P < 0.01). CONCLUSION: The combination of PESI-MS and machine learning distinguished CRLM from non-cancer tissue with high accuracy. Phospholipids categorized as monounsaturated fatty acids contributed to the difference between CRLM and normal parenchyma and might also be a useful diagnostic biomarker and therapeutic target for CRLM.

Natural Herbal Estrogen-Mimetics (Phytoestrogens) Promote the Differentiation of Fallopian Tube Epithelium into Multi-Ciliated Cells via Estrogen Receptor Beta.

Phytoestrogens are herbal polyphenolic compounds that exert various estrogen-like effects in animals and can be taken in easily from a foodstuff in daily life. The fallopian tube lumen, where transportation of the oocyte occurs, is lined with secretory cells and multi-ciliated epithelial cells. Recently, we showed that estrogen induces multi-ciliogenesis in the porcine fallopian tube epithelial cells (FTECs) through the activation of the estrogen receptor beta (ERß) pathway and simultaneous inhibition of the Notch pathway. Thus, ingested phytoestrogens may induce FTEC ciliogenesis and thereby affect the fecundity. To address this issue, we added isoflavones (genistein, daidzein, or glycitin) and coumestan (coumestrol) to primary culture FTECs under air-liquid interface conditions and assessed the effects of each compound. All phytoestrogens except glycitin induced multi-ciliated cell differentiation, which followed Notch signal downregulation. On the contrary, the differentiation of secretory cells decreased slightly. Furthermore, genistein and daidzein had a slight effect on the proportion of proliferating cells exhibited by Ki67 expression. Ciliated-cell differentiation is inhibited by the ERß antagonist, PHTPP. Thus, this study suggests that phytoestrogens can improve the fallopian tube epithelial sheet homeostasis by facilitating the genesis of multi-ciliated cells and this effect depends on the ERß-mediated pathway.

Dynamic Changes in Ultrastructure of the Primary Cilium in Migrating Neuroblasts in the Postnatal Brain.

New neurons, referred to as neuroblasts, are continuously generated in the ventricular-subventricular zone of the brain throughout an animal's life. These neuroblasts are characterized by their unique potential for proliferation, formation of chain-like cell aggregates, and long-distance and high-speed migration through the rostral migratory stream (RMS) toward the olfactory bulb (OB), where they decelerate and differentiate into mature interneurons. The dynamic changes of ultrastructural features in postnatal-born neuroblasts during migration are not yet fully understood. Here we report the presence of a primary cilium, and its ultrastructural morphology and spatiotemporal dynamics, in migrating neuroblasts in the postnatal RMS and OB. The primary cilium was observed in migrating neuroblasts in the postnatal RMS and OB in male and female mice and zebrafish, and a male rhesus monkey. Inhibition of intraflagellar transport molecules in migrating neuroblasts impaired their ciliogenesis and rostral migration toward the OB. Serial section transmission electron microscopy revealed that each migrating neuroblast possesses either a pair of centrioles or a basal body with an immature or mature primary cilium. Using immunohistochemistry, live imaging, and serial block-face scanning electron microscopy, we demonstrate that the localization and orientation of the primary cilium are altered depending on the mitotic state, saltatory migration, and deceleration of neuroblasts. Together, our results highlight a close mutual relationship between spatiotemporal regulation of the primary cilium and efficient chain migration of neuroblasts in the postnatal brain.SIGNIFICANCE STATEMENT Immature neurons (neuroblasts) generated in the postnatal brain have a mitotic potential and migrate in chain-like cell aggregates toward the olfactory bulb. Here we report that migrating neuroblasts possess a tiny cellular protrusion called a primary cilium. Immunohistochemical studies with zebrafish, mouse, and monkey brains suggest that the presence of the primary cilium in migrating neuroblasts is evolutionarily conserved. Ciliogenesis in migrating neuroblasts in the rostral migratory stream is suppressed during mitosis and promoted after cell cycle exit. Moreover, live imaging and 3D electron microscopy revealed that ciliary localization and orientation change during saltatory movement of neuroblasts. Our results reveal highly organized dynamics in maturation and positioning of the primary cilium during neuroblast migration that underlie saltatory movement of postnatal-born neuroblasts.

Sonic hedgehog enhances calcium oscillations in hippocampal astrocytes.

Sonic hedgehog (SHH) is important for organogenesis during development. Recent studies have indicated that SHH is also involved in the proliferation and transformation of astrocytes to the reactive phenotype. However, the mechanisms underlying these are unknown. Involvement of SHH signaling in calcium (Ca) signaling has not been extensively studied. Here, we report that SHH and Smoothened agonist (SAG), an activator of the signaling receptor Smoothened (SMO) in the SHH pathway, activate Ca oscillations in cultured murine hippocampal astrocytes. The response was rapid, on a minute time scale, indicating a noncanonical pathway activity. Pertussis toxin blocked the SAG effect, indicating an involvement of a Gi coupled to SMO. Depletion of extracellular ATP by apyrase, an ATP-degrading enzyme, inhibited the SAG-mediated activation of Ca oscillations. These results indicate that SAG increases extracellular ATP levels by activating ATP release from astrocytes, resulting in Ca oscillation activation. We hypothesize that SHH activates SMO-coupled Gi in astrocytes, causing ATP release and activation of Gq/11-coupled P2 receptors on the same cell or surrounding astrocytes. Transcription factor activities are often modulated by Ca patterns; therefore, SHH signaling may trigger changes in astrocytes by activating Ca oscillations. This enhancement of Ca oscillations by SHH signaling may occur in astrocytes in the brain in vivo because we also observed it in hippocampal brain slices. In summary, SHH and SAG enhance Ca oscillations in hippocampal astrocytes, Gi mediates SAG-induced Ca oscillations downstream of SMO, and ATP-permeable channels may promote the ATP release that activates Ca oscillations in astrocytes.

Lipidome-based rapid diagnosis with machine learning for detection of TGF-ß signalling activated area in head and neck cancer.

BACKGROUND: Several pro-oncogenic signals, including transforming growth factor beta (TGF-ß) signalling from tumour microenvironment, generate intratumoural phenotypic heterogeneity and result in tumour progression and treatment failure. However, the precise diagnosis for tumour areas containing subclones with cytokine-induced malignant properties remains clinically challenging. METHODS: We established a rapid diagnostic system based on the combination of probe electrospray ionisation-mass spectrometry (PESI-MS) and machine learning without the aid of immunohistological and biochemical procedures to identify tumour areas with heterogeneous TGF-ß signalling status in head and neck squamous cell carcinoma (HNSCC). A total of 240 and 90 mass spectra were obtained from TGF-ß-unstimulated and -stimulated HNSCC cells, respectively, by PESI-MS and were used for the construction of a diagnostic system based on lipidome. RESULTS: This discriminant algorithm achieved 98.79% accuracy in discrimination of TGF-ß1-stimulated cells from untreated cells. In clinical human HNSCC tissues, this approach achieved determination of tumour areas with activated TGF-ß signalling as efficiently as a conventional histopathological assessment using phosphorylated-SMAD2 staining. Furthermore, several altered peaks on mass spectra were identified as phosphatidylcholine species in TGF-ß-stimulated HNSCC cells. CONCLUSIONS: This diagnostic system combined with PESI-MS and machine learning encourages us to clinically diagnose intratumoural phenotypic heterogeneity induced by TGF-ß.

Rapid automated diagnosis of primary hepatic tumour by mass spectrometry and artificial intelligence.

BACKGROUND AND AIMS: Complete surgical resection with negative margin is one of the pillars in treatment of liver tumours. However, current techniques for intra-operative assessment of tumour resection margins are time-consuming and empirical. Mass spectrometry (MS) combined with artificial intelligence (AI) is useful for classifying tissues and provides valuable prognostic information. The aim of this study was to develop a MS-based system for rapid and objective liver cancer identification and classification. METHODS: A large dataset derived from 222 patients with hepatocellular carcinoma (HCC, 117 tumours and 105 non-tumours) and 96 patients with mass-forming cholangiocarcinoma (MFCCC, 50 tumours and 46 non-tumours) were analysed by Probe Electrospray Ionization (PESI) MS. AI by means of support vector machine (SVM) and random forest (RF) algorithms was employed. For each classifier, sensitivity, specificity and accuracy were calculated. RESULTS: The overall diagnostic accuracy exceeded 94% in both the AI algorithms. For identification of HCC vs non-tumour tissue, RF was the best, with 98.2% accuracy, 97.4% sensitivity and 99% specificity. For MFCCC vs non-tumour tissue, both algorithms gave 99.0% accuracy, 98% sensitivity and 100% specificity. CONCLUSIONS: The herein reported MS-based system, combined with AI, permits liver cancer identification with high accuracy. Its bench-top size, minimal sample preparation and short working time are the main advantages. From diagnostics to therapeutics, it has the potential to influence the decision-making process in real-time with the ultimate aim of improving cancer patient cure.

Detection of potential new biomarkers of atherosclerosis by probe electrospray ionization mass spectrometry.

INTRODUCTION: Atherosclerotic diseases are the leading cause of death worldwide. Biomarkers of atherosclerosis are required to monitor and prevent disease progression. While mass spectrometry is a promising technique to search for such biomarkers, its clinical application is hampered by the laborious processes for sample preparation and analysis. METHODS: We developed a rapid method to detect plasma metabolites by probe electrospray ionization mass spectrometry (PESI-MS), which employs an ambient ionization technique enabling atmospheric pressure rapid mass spectrometry. To create an automatic diagnosis system of atherosclerotic disorders, we applied machine learning techniques to the obtained spectra. RESULTS: Using our system, we successfully discriminated between rabbits with and without dyslipidemia. The causes of dyslipidemia (genetic lipoprotein receptor deficiency or dietary cholesterol overload) were also distinguishable by this method. Furthermore, after induction of atherosclerosis in rabbits with a cholesterol-rich diet, we were able to detect dynamic changes in plasma metabolites. The major metabolites detected by PESI-MS included cholesterol sulfate and a phospholipid (PE18:0/20:4), which are promising new biomarkers of atherosclerosis. CONCLUSION: We developed a remarkably fast and easy method to detect potential new biomarkers of atherosclerosis in plasma using PESI-MS.

Hepatitis B virus prevents excessive viral production via reduction of cell death-inducing DFF45-like effectors.

The relationship between hepatitis B virus (HBV) infection and lipid accumulation remains largely unknown. In this study, we investigated the effect of HBV propagation on lipid droplet growth in HBV-infected cells and HBV-producing cell lines, HepG2.2.15 and HBV-inducible Hep38.7-Tet. The amount of intracellular triglycerides was significantly reduced in HBV-infected and HBV-producing cells compared with HBV-lacking control cells. Electron and immunofluorescent microscopic analyses showed that the average size of a single lipid droplet (LD) was significantly less in the HBV-infected and HBV-producing cells than in the HBV-lacking control cells. Cell death-inducing DFF45-like effectors (CIDEs) B and C (CIDEB and CIDEC), which are involved in LD expansion for the improvement of lipid storage, were expressed at a significantly lower level in HBV-infected or HBV-producing cells than in HBV-lacking control cells, while CIDEA was not detected in those cells regardless of HBV production. The activity of the CIDEB and CIDEC gene promoters was impaired in HBV-infected or HBV-producing cells compared to HBV-lacking control cells, while CIDEs potentiated HBV core promoter activity. The amount of HNF4α, that can promote the transcription of CIDEB was significantly lower in HBV-producing cells than in HBV-lacking control cells. Knockout of CIDEB or CIDEC significantly reduced the amount of supernatant HBV DNA, intracellular viral RNA and nucleocapsid-associated viral DNA, while the expression of CIDEB or CIDEC recovered HBV production in CIDEB- or CIDEC-knockout cells. These results suggest that HBV regulates its own viral replication via CIDEB and CIDEC.

In vivo endoscopic mass spectrometry using a moving string sampling probe.

At present, endoscopy relies almost exclusively on optical microscopy and the accurate analysis such as MS interrogation is performed ex situ using biopsy. In this work, a novel probing system is developed to perform in situ and in vivo endoscopic mass spectrometry using a moving string for the sampling and transportation of material. A prototype of a mass spectrometric endoscope is constructed using an industrial endoscope and a commercial mass spectrometer. The sampling system consists of a moving cotton thread driven by motorized pulleys. When the target surface is touched by the sampling probe, the cotton thread "wipes" and transports the adhered sample to the ion source. Depending on the target analytes, desorption electrospray and atmospheric pressure chemical ionization sources are employed interchangeably for the desorption and ionization. The surface under analysis is not subjected to heat, organic solvents, high voltage or charged droplets. In situ endoscopic MS of a living mouse and surface analysis inside a volunteer subject's mouth are demonstrated.

Genetically encoded calcium indicator illuminates calcium dynamics in primary cilia.

Visualization of signal transduction in live primary cilia constitutes a technical challenge owing to the organelle's submicrometer dimensions and close proximity to the cell body. Using a genetically encoded calcium indicator targeted to primary cilia, we visualized calcium signaling in cilia of mouse fibroblasts and kidney cells upon chemical or mechanical stimulation with high specificity, high sensitivity and wide dynamic range.

TRPV4 regulates the integrity of the blood-cerebrospinal fluid barrier and modulates transepithelial protein transport.

The diffusion of materials from systemic circulation to the central nervous system (CNS) is restricted by the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB). Choroid plexus epithelial cells (CPECs) of the brain ventricles constitute the BCSFB and regulate the infiltration of plasma proteins as well as immune cells into the interstitium of the CNS. The barrier function is altered in pathologic conditions. However, the regulatory mechanism of BCSFB is not fully understood. Here, we investigated the function of transient receptor potential vanilloid 4 (TRPV4), a polymodally gated divalent cation channel that is highly expressed in CPECs. TRPV4 was localized broadly on the apical membrane in swine CPECs, in contrast with an intense ciliary localization found on other cell types. Treatment with the TRPV4-specific agonist, GSK1016790A (GSK; EC50 34 nM), induced a robust calcium influx and an immediate serine/threonine protein phosphorylation. The agonist treatment induced a marked decrease in the amount of filamentous actin and disintegrated the cell junctions in 10-20 minutes. In contrast, inhibition of the basal TRPV4 activity with the TRPV4-specific antagonist, HC067047 (HC; IC50 74 nM), reduced the basolateral-to-apical transport of α-2-macroglobulin (A2M). Overall, this study demonstrated a novel physiologic function of TRPV4 in the regulation of BCSFB permeability.

[Fragments Woven into a Whole: A New Approach to the Diagnosis of Cancer through Mass Spectrometry and Machine-Learning].

Conventionally, a definitive diagnosis of cancer is derived from histopathological diagnostics based on morphological criteria that are difficult to standardize on a quantifiable basis. On the other hand, while molecular tumor markers and blood biochemical profiles give quantitative values evaluated by objective criteria, these parameters are usually generated by deductive methods such as peak extraction. Therefore, some of the data that may contain useful information on specimens are discarded. To overcome the disadvantages of these methods, we have developed a new approach by employing both mass spectrometry and machine-learning for cancer diagnosis. Probe electrospray ionization (PESI) is a derivative of electrospray ionization that uses a fine acupuncture needle as a sample picker as well as an ion emitter for mass spectrometry. This method enables us to ionize very small tissue samples up to a few pico liters in the presence of physiological concentrations of inorganic salts, without the need for any sample pretreatment. Moreover, as this technique makes it possible to ionize all components with minimal suppression effects, we can retrieve much more molecular information from specimens. To make the most of data enriched with lipid compounds and substances with lower molecular weights such as carbohydrates, we employed machine-learning named the dual penalized logistic regression machine (dPLRM). This method is completely different from pattern-matching in that it discriminates categories by projecting the spectral data into a mathematical space with very high dimensions, where final judgment is made. We are now approaching the final clinical trial to validate the usefulness of our system.

Biomolecular analysis and biological tissue diagnostics by electrospray ionization with a metal wire inserted gel-loading tip.

A metal wire-inserted disposable gel-loading tip was examined as an electrospray emitter. Its performance was similar to that of conventional electrospray ionization (ESI) with a relatively low flow rate (~100 nL/min) and without the need for solvent pumps. It was also used as an emitter for solid probe-assisted ESI (SPA-ESI) (e.g., biofluid was sampled from the biological tissue by a needle and was inserted into the solvent-preloaded gel-loading tip). Selective detection of lipids and proteins, such α and ß chains of hemoglobin could be accomplished by choosing appropriate solvents. A suitable protocol for cancer diagnosis was established by this method. A good figure of merit of this method is its applicability to biological tissue diagnostics with high cost efficiency and on a disposable basis.

Real-time diagnosis of chemically induced hepatocellular carcinoma using a novel mass spectrometry-based technique.

Real-time analyses of hepatocellular carcinoma were performed in living mice to assess the applicability of probe electrospray ionization-mass spectrometry (PESI-MS) in medical diagnosis. The number of peaks and the abundance of ions corresponding to triacylglycerols (TAGs) were higher in cancerous tissues than in noncancerous tissues. Multiple sequential scans of the specimens were performed along a predetermined line extending over the noncancerous region to detect the boundary of the cancerous region. Our system successfully discriminated the noncancerous and cancerous tissues based on the intensities of the TAG ions. These results highlight the potential application of PESI-MS for clinical diagnosis in cancer.