J Pathol 2019 09 2;249(1):3-5. Epub 2019 Jul 2.
Department of Pathology, Indiana University School of Medicine, Indianapolis, IN, USA.
A recent study has identified gene mutations involving the MAPK/ERK pathway, particularly the HRAS gene, in all inverted urothelial papillomas (IUPs), in the absence of pathway mutations in TERT promoter, FGFR3, and TP53/RB1genes. Neither recurrence nor progression was observed in IUPs. These data support several longstanding hypotheses: (1) IUPs are benign and do not recur or progress; (2) they harbor mutations that are different from those of urothelial carcinoma; and (3) they arise through different molecular mechanisms than low- or high-grade urothelial carcinoma. Read More