Abstract
The diagnosis of malignant biliary strictures remains problematic, especially in the
perihilar region and in primary sclerosing cholangitis (PSC). Conventional cytology
obtained during endoscopic retrograde cholangiography (ERC)-guided brushings of biliary
strictures is suboptimal due to limited sensitivity, albeit it remains the gold standard
with a high specificity. Emerging technologies are being developed and validated to
address this pressing unmet patient need. Such technologies include enhanced visualization
of the biliary tree by cholangioscopy, intraductal ultrasound, and confocal laser
endomicroscopy. Conventional cytology can be aided by employing complementary and
advanced cytologic techniques such as fluorescent in situ hybridization (FISH), and
this technique should be widely adapted. Interrogation of bile and serum by examining
extracellular vesicle number and cargo, and exploiting next-generation sequencing
and proteomic technologies, is also being explored. Examination of circulating cell-free
deoxyribonucleic acid (cfDNA) for differentially methylated regions is a promising
test which is being rigorously validated. The special expertise required for these
analyses has to date hampered their validation and adaptation. Herein, we will review
these emerging technologies to inform the reader of the progress made and encourage
further studies, as well as adaptation of validated approaches.
Keywords
cell-free DNA - differentially methylated regions - FISH
