Related Experiment Video
Updated: May 31, 2026
Cell Population Analyses During Skin Carcinogenesis
Published on: August 21, 2013
Immunohistochemical analysis of SMARCB1/INI-1 expression in collecting duct carcinoma
Hillary Elwood1, Alcides Chaux, Luciana Schultz
1Department of Pathology, Johns Hopkins University, Baltimore, Maryland 21231-2410, USA.
Objectives:
Collecting duct carcinoma (CDC) is a rare and aggressive renal tumor with a tendency to involve the renal sinus. CDC displays variable morphologic features that can overlap with those of renal medullary carcinoma. The loss of SMARCB1/INI1 tumor suppressor gene, initially found in pediatric malignant rhabdoid tumors of the central nervous system, kidneys, and soft tissues, was also recently described in renal medullary carcinoma. The current immunohistochemical study assessed SMARCB1/INI1 expression in a series of CDCs.
Methods:
A total of 20 archival cases of CDC were used to construct a tissue microarray. Each tumor was spotted 3-7 times; benign tissue from the same specimen was also included when available. The immunoexpression of SMARCB1/INI1 was evaluated using BAF47, a monoclonal mouse antibody directed against the SMARCB1/INI1 gene product. Nuclear staining was considered as indicative of SMARCB1/INI1 expression.
Results:
The complete loss of SMARCB1/INI1 expression was observed in 3 of 20 cases of CDC. Another 3 cases revealed focal and weak intensity staining. The remaining tumors showed multifocal or diffuse SMARCB1/INI1 expression with variable staining intensity. No significant differences were found in the clinicopathologic and outcome features regarding SMARCB1/INI1 status.
Conclusions:
The complete loss of SMARCB1/INI1 immunoexpression was found in 15% of CDC. No differences were found between the SMARCB1/INI1 positive and negative cases regarding the clinicopathologic and outcome features. Our results suggest that some CDC cases might be associated with genetic alterations involving the SMARCB1/INI1 gene. In addition, SMARCB1/INI1 immunoexpression seems to be of limited value in the differential diagnosis of CDC versus renal medullary carcinoma, although these results require additional validation.
Insights
Collecting duct carcinoma (CDC) shows SMARCB1/INI1 gene loss in 15% of cases. This loss did not correlate with clinical features, suggesting potential genetic alterations in some rare renal tumors.
Area of Science:
- Oncology
- Pathology
- Genetics
Background:
- Collecting duct carcinoma (CDC) is a rare, aggressive renal tumor.
- CDC shares morphologic overlap with renal medullary carcinoma.
- SMARCB1/INI1 gene loss is implicated in pediatric rhabdoid tumors and renal medullary carcinoma.
Purpose of the Study:
- To assess SMARCB1/INI1 expression in Collecting duct carcinoma (CDC).
- To investigate the potential role of SMARCB1/INI1 alterations in CDC pathogenesis.
- To evaluate the utility of SMARCB1/INI1 immunoexpression in differentiating CDC from renal medullary carcinoma.
Main Methods:
- A tissue microarray was constructed from 20 archival CDC cases.
- Immunohistochemistry using BAF47 antibody assessed SMARCB1/INI1 expression.
- Nuclear staining intensity and pattern were evaluated.
Main Results:
- Complete loss of SMARCB1/INI1 expression was found in 3 out of 20 (15%) CDC cases.
- Three additional cases showed focal, weak staining.
- No significant differences in clinicopathologic or outcome features were observed based on SMARCB1/INI1 status.
Conclusions:
- Complete SMARCB1/INI1 loss occurs in 15% of CDC, suggesting potential genetic alterations.
- SMARCB1/INI1 status did not correlate with clinical or outcome features in this cohort.
- SMARCB1/INI1 immunoexpression has limited differential diagnostic value between CDC and renal medullary carcinoma, pending further validation.
More Related Videos
10:11Immunohistochemical Staining of B7-H1 (PD-L1) on Paraffin-embedded Slides of Pancreatic Adenocarcinoma Tissue
Published on: January 3, 2013
08:53In Vivo Immunofluorescence Localization for Assessment of Therapeutic and Diagnostic Antibody Biodistribution in Cancer Research
Published on: September 16, 2019