Demethylases of H3 lysine 27 (H3K27) expression in urothelial carcinoma (UC) of the urinary bladder

BACKGROUND: Ubiquitously Transcribed Tetracopeptide Repeat on X Chromosome (UTX) and Jumonji Domain-Containing Protein 3 (JMJD3) are histone H3 lysine 27 (H3K27) demethylases that are found to play tumour suppressor or oncogenic roles in many cancers. However, their roles in urothelial carcinoma (UC) have not been well studied.

OBJECTIVE: This study investigated UTX and JMJD3 protein expression patterns in UC and assess their clinical significance.

PATIENTS AND METHODS: Immunohistochemistry (IHC) method was performed on formalin-fixed paraffin-embedded (FFPE) of UC tissues and compared to the normal bladder tissues from the autopsy specimen. The staining intensity of FFPE tissues were captured with the nuclear and overall positive pixels quantified using Aperio ImageScope software.

RESULTS: JMJD3 protein uptake was present in both nucleus and cytoplasm but UTX protein was predominantly seen in the cytoplasm of UC tissue. UTX was under expressed whereas JMJD3 was over expressed in UC compared to normal bladder. UTX and JMJD3 were not related to clinical stage and grade. However, significant association between JMJD3 expression and invasiveness of tumour (p<0.05) was noted, especially in MIBC group (88.9%). UTX and JMJD3 did not yield any significance as prognostic factors for diseasespecific survival.

CONCLUSIONS: Low expression of UTX protein in UC may indicate possible loss of its tumour suppressor activity and higher JMJD3 protein expression may indicate oncogenic activity. Hence, JMJD3 protein could be a potential diagnostic biomarker in detecting bladder UC of higher stages. Further investigation needed to study the dysregulation of this protein expression with associated gene expression.