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Updated: Aug 6, 2026
RhoC GTPase Activation Assay
Published on: August 22, 2010
Immunohistochemical Expression of RhoJ Protein in Breast Carcinoma
Xavier Catteau1,2, Manon Charry1, Justine Allard3
1CurePath Laboratory (Chirec Institute-Brussels, CHU Tivoli-La Louvière).
Background:
Breast cancer is the most common form of cancer diagnosed in women. Breast cancer cells gain the expression of mesenchymal-specific genes in a process known as epithelial-mesenchymal transition (EMT). RhoJ, a small Rho GTPase, is a key regulator that promotes resistance to a wide range of chemotherapeutic agents in epithelial-mesenchymal transition tumor cells.
Methods:
Sixty-three cases of invasive breast carcinoma and 10 cases of normal breast tissue were collected to examine the protein's expression of RhoJ in epithelial and stromal cells. Two pathologists performed the H-Score in a blinded fashion.
Results:
Normal ductal cells expressed RhoJ moderately to sometimes intensely. Normal breast stroma showed low to moderate expression in 95% of cases. All malignant ductal cells, except for 2 cases of metaplastic carcinoma, showed diffuse and intense expression. Stromal cells in invasive areas showed low to moderate expression. We found no statistically significant difference in RhoJ expression between carcinoma and normal breast tissue or between carcinoma subtypes (no special type vs. lobular; triple negative vs. luminal). Interestingly, we found a lower expression of RhoJ in metaplastic carcinomas (2 cases of spindle cell variants).
Conclusions:
High levels of RhoJ expression in most breast carcinomas suggest it could be a valuable therapeutic target. However, further studies involving a larger patient cohort are necessary to validate these findings.
Insights
High RhoJ protein expression in most breast cancers suggests it could be a therapeutic target. Further research is needed to confirm its role in breast cancer treatment.
Area of Science:
- Oncology
- Molecular Biology
- Cell Biology
Background:
- Breast cancer is the most common cancer in women.
- Epithelial-mesenchymal transition (EMT) drives breast cancer progression and chemoresistance.
- RhoJ GTPase is implicated in EMT and chemoresistance.
Purpose of the Study:
- To investigate RhoJ protein expression in normal and malignant breast tissues.
- To assess the potential of RhoJ as a therapeutic target in breast cancer.
Main Methods:
- Analysis of 63 invasive breast carcinoma and 10 normal breast tissue samples.
- Immunohistochemical examination of RhoJ protein expression by two pathologists using H-Score.
- Blinded assessment to ensure objectivity.
Main Results:
- RhoJ was moderately to intensely expressed in normal ductal cells.
- Most malignant ductal cells exhibited diffuse and intense RhoJ expression.
- No significant difference in RhoJ expression was found between normal and malignant tissues or subtypes, except for lower expression in metaplastic carcinomas.
Conclusions:
- Elevated RhoJ expression in most breast carcinomas indicates its potential as a therapeutic target.
- Larger patient cohorts are required for validation of RhoJ as a therapeutic target.
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