Dynamic gene expression pattern in zebrafish gallbladder: an experimental study

Gallbladder cancer (GBC) is one of the common biliary tract malignancies that is often associated with late presentation of clinical symptoms resulting in poor prognosis, thereby considerably increasing the mortality rate. Geographic and ethnic variations are one of the major causes of GBC incidence. However, in addition to genetic susceptibility to GBC, other factors like age, obesity, sex, and exposure to certain heavy chemicals may also lead to the incidence of GBC. Most of GBC research has so far used traditional cell culture systems. Recently, newer approaches using 2D and 3D cultures, xenograft models, and organoids are also becoming popular. However, whole organism model systems for GBC research have not yet been established. In this study, the authors propose the use of zebrafish as a model organism to study GBC. However, the zebrafish gallbladder is relatively unexplored besides the anatomical features. Here, the authors unravel and then compare the unique transcriptomic profile of zebrafish gallbladder with humans to identify genes consistently expressed in both species. The authors provide a comprehensive list of all gallbladder specific genes in zebrafish that also have their orthologous counterparts in humans. Therefore, they can be used as potential biomarkers for gallbladder transcriptomic profile. To the best of our knowledge, this is the only study so far to provide a complete genomic expression profile of zebrafish gallbladder along with an exhaustive cross-species comparison, thus paving the path for using zebrafish as a model organism to study GBC and help identify novel biomarkers for its early detection and diagnosis.