Clinical utility of methionyl-tRNA synthetase 1 immunostaining in cytologic brushings of indeterminate biliary strictures: a multicenter prospective study

Sung Ill Jang, Ji Hae Nahm, Nam Hoon Kwon, Seok Jeong, Tae Hoon Lee, Jae Hee Cho, Chang Il Kwon, Dong Uk Kim, Joon Mee Kim, Hyun Deuk Cho, Hye Sun Lee, Sunghoon Kim, Dong Ki Lee

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Background and Aims: Endobiliary brushings are routinely used in the diagnosis, treatment, and prognostication of biliary strictures. However, standard Papanicolaou (Pap) staining has a low sensitivity in this setting, and the accuracy of brush cytology has not been established for indeterminate strictures. We therefore evaluated the diagnostic merit of methionyl-transfer RNA synthetase 1 (MARS1) immunofluorescence (IF) staining in such cytologic specimens. Methods: During ERCP, endobiliary brushings were obtained from patients with extrahepatic biliary strictures prospectively enrolled at 6 tertiary hospitals. Using liquid-based cytologic preparations of these samples, we performed Pap and MARS1 IF staining. Results: In total, 240 patients were eligible; of these, we compared the Pap and MARS1 IF staining results of 218 (malignant, 157; benign, 61). By conventional Pap staining, the diagnoses were distributed as follows: malignant, 55; suspicious of malignancy, 60; atypical, 45; negative for malignancy, 58. MARS1 IF staining was strongly positive in malignant biliary stricture but not so in specimens negative for malignancy. The diagnostic parameters (sensitivity, specificity, positive predictive value, negative predictive value, and accuracy) of the MARS1 IF (93.6%, 96.7%, 98.7%, 85.5%, and 94.5%, respectively) and conventional Pap (73.2%, 100%, 100%, 59.2%, and 80.7%, respectively) staining methods differed significantly (P < .0001). Conclusions: The high sensitivity and accuracy of MARS1 IF staining enabled the detection of malignancy in patients with biliary strictures. Further prospective studies are needed to validate our findings. (Clinical trial registration number: NCT03708445.)

Original languageEnglish
Pages (from-to)733-741.e4
JournalGastrointestinal endoscopy
Issue number4
Publication statusPublished - 2021 Oct

Bibliographical note

Funding Information:
DISCLOSURE: The following authors disclosed financial relationships: S. I. Jang, J. H. Nahm, S. Kim, D. K. Lee: Financial interests in Oncotag Diagnostics. All other authors disclosed no financial relationships. Research support for this study was provided by grants NRF-2014M3A6A4074817 (D. K. Lee), NRF-M3A6A4-2010-0029785 (S. Kim), and NRF2015M3A6A4065724 (N.H. Kwon) from the Global Frontier National Research Foundation, Ministry of Science and ICT (MSIT) of Korea; grants NRF-2017M3A9F7079378 (N. H. Kwon) and NRF-2018M3A9F7062524 (S. I. Jang) from the National Research Foundation, MSIT of Korea.

Publisher Copyright:
© 2021 American Society for Gastrointestinal Endoscopy

All Science Journal Classification (ASJC) codes

  • Radiology Nuclear Medicine and imaging
  • Gastroenterology


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