In our cohort, both TERT mutated enteric BAC specimens (AE-3 and AE-6) additionally exhibited colorectal characteristics, i.e. alterations in SMAD4 and PTEN. Taken together, the current results for BAC from our study and from Roy et al. present BAC as a distinct entity exhibiting both characteristics of urothelial (e.g. TERT mutations, alterations in chromatin remodelling) and colorectal cancer (e.g. alterations in Wnt pathway) [9]. Here, SMAD4 is linked to colorectal cancer.