The Clonal Origin Of Multifocal Urothelial Carcinoma Studied By Fluorescence In Situ Hybridization

Objective: Multifocal urothelial carcinoma is common, with the characteristics ofhigh recurrence rate, high rate of progression and high mortality. Currently, there is nodefinite conclusion to the clone origin. It is important to clarify the cloning mechanismand clone origin for understanding the biological characteristics, prognosis, guidingclinical treatment and postoperative monitoring. Chromosomal aberrations in urothelialcarcinoma is a very common event. Fluorescence in situ hybridization(FISH) is a newtechnique to detect chromosomal aberrations. The present study aims to study the clonalorigin of multifocal urothelial carcinoma by detecting chromosomal aberrations with FISH.Methods: There were17cases of multifocal urothelial carcinoma with total of44tumors included in the study. Ten of them were simultaneous urothelial carcinoma and9were metachronous. Two cases have both simultaneous tumor and metachronous tumor.Aberration of urothelial carcinoma with high frequency at3、7、9、17chromosomes wereselected and detected by using CSP3/CSP7DNA probe combinations and GLP p16/CSP17DNA probe combinations. Chromosomal aberrations type was analyzed andcompared to determine the clonality of multifocal tumors.Results: Of the17cases,15cases(88.2%) shared concordant type ofchromosomal aberrations, and considered of common clonal origin,2cases weredetected of discordant type of chromosomal aberrations and were consideredindependent clonal origin. And both of them were metachronous tumors, and theprimary tumor and subsequent tumor had an interval of more than5years.Conclusions: Multifocal urothelial carcinomas are mostly of monoclonal origin.Some metachronous tumors are most probably polyclonal origin and always with a longintervals.