Publication Date:
2013-11-27
Description:
Aims The aim of this study was to examine the status of BRM, a key SWI/SNF complex subunit, in clear cell renal cell carcinomas (RCC), and to analysis the histopathology, immunophenotype, molecular features, and prognosis of the BRM-negative cases. Methods and results We identified 19 cases of grade 4 tumors lacking of BRM expression among 625 clear cell RCC. All 19 cases exhibited poorly differentiated features, 13 showed pure poorly differentiated morphology while 6 were composite tumors mixed with typical low grade component. Besides negative BRM expression, the immunophenotype of these cases was similar to clear cell RCC. VHL gene mutations were identified in 9/19 patients (47%). Chromosome 3p deletion was detected in 11/13 poorly differentiated RCCs and both areas of 5/5 composite tumors. All poorly differentiated tumor areas showed polysomy of chromosome 3. No losses or gains of chromosome 3 were observed in low grade tumor areas of 5/5 composite RCCs. Conclusions We have shown that a loss of BRM expression is a common feature among poorly differentiated tumors in clear cell RCCs. We hypothesize that loss of BRM expression is involved in tumor dedifferentiation in clear cell RCCs and may play an important role during tumor progression. This article is protected by copyright. All rights reserved.
Print ISSN:
0309-0167
Electronic ISSN:
1365-2559
Topics:
Medicine
