CTLA4 and colorectal cancer: We did not extend examination to UC patients who developed colorectal cancer to study the pattern of microbiota in these patients and cases with CRC and dysbiosis should be investigated for tumoral CTLA-4 expression to initiate a predictive analysis for treatment response before using capecitabine which can downregulate CTLA-4 [16]; these points could be hot topics for future research and are beyond the scope of the manuscript.