Secondary Ion Mass Spectrometry Analysis of Renal Cell Carcinoma with Electrospray Droplet Ion Beams

New strategy for evaluating pancreatic tissue specimens from endoscopic ultrasound-guided fine needle aspiration and surgery

Background and Aim

Preoperative histological evaluation of pancreatic neoplasms is important for guiding the resection strategy and preventing postoperative adverse events. However, conventional endoscopic methods have technical limitations that reduce the accuracy of the histopathological examination. Probe electrospray ionization mass spectrometry (PESI‐MS) may be a useful technique for rapidly evaluating small specimens.

Methods

This single‐center prospective study included patients with pancreatic neoplasms between October 2018 and December 2019. Pancreatic ductal adenocarcinoma (PDAC) specimens were obtained via endoscopic ultrasound‐guided fine needle aspiration (EUS‐FNA) and non‐neoplastic tissue was obtained via surgery. Specimens were subjected to PESI‐MS and the mass spectra were analyzed using partial least squares regression‐discriminant analysis.

Results

The study included 40 patients with 20 nonneoplastic specimens and 19 PDAC specimens (1 case of neuroendocrine carcinoma was omitted). All nonneoplastic specimens were sufficient for PESI‐MS analysis, although only 7 of 19 PDAC specimens were sufficient for PESI‐MS analysis because of poor sample quality or insufficient quantity (<1 mg). Among the 27 analyzed cases, the mass spectra clearly differentiated between the PDAC and nonneoplastic specimens.

Conclusions

This study revealed that PESI‐MS could differentiate between PDAC and nonneoplastic specimens, even in cases where EUS‐FNA produced very small specimens.

Mapping chemotherapeutic drug distribution in cancer cell spheroids using 2D-TOF-SIMS and LESA-TIMS-MS

Three-dimensional (3D) cancer cell cultures grown in the form of spheroids are effective models for the study of in vivo-like processes simulating cancer tumor pharmacological dynamics and morphology. In this study, we show the advantages of Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) combined with in situ Liquid Extraction Surface Analysis coupled to trapped Ion Mobility Spectrometry Mass Spectrometry (LESA-TIMS-TOF MS) for high spatial resolution mapping and quantitation of ABT-737, a chemotherapeutic drug, at the level of single human colon carcinoma cell spheroids (HCT 116 MCS). 2D-TOF-SIMS studies of consecutive sections (∼16 μm thick slices) showed that ABT-737 is homogenously distributed in the outer layers of the HCT 116 MCS. Complementary in situ LESA-TIMS-TOF MS/MS measurements confirmed the presence of the ABT-737 drug in the MCS slides by the observation of the molecular ion [M + H]+m/z and mobility, and the charateristic fragmentation pattern. LESA-TIMS-TOF MS allowed a quantitative assessment of the ABT-737 drug of the control MCS slice spiked with ABT-737 standard over the 0.4-4.1 ng range and MCS treated starting at 10 μM for 24 h. These experiments showcase an effective protocol for unambigous characterization and 3D mapping of chemotherapeutic drug distribution at the single MCS level.