Mediator Complex Subunit MED1 Protein Expression Is Decreased during Bladder Cancer Progression
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Niklas Klümper1, Isabella Syring2, Wenzel Vogel1
1Pathology of the University Medical Center Schleswig-Holstein, Campus Luebeck and the Research Center Borstel, Leibniz Center for Medicine and Biosciences, Luebeck, Germany.
Introduction:
Bladder cancer (BCa) is among the most frequent cancer entities and relevantly contributes to cancer-associated deaths worldwide. The multi-protein Mediator complex is a central regulator of the transcriptional machinery of protein-coding genes and has been described to be altered in several malignancies. MED1, a subunit of the tail module, was described to negatively modulate expression of metastasis-related genes and to be downregulated in melanoma and lung cancer. In contrast, MED1 hyperactivity was described in breast and prostate cancer, likely due its function as a hub for nuclear hormone receptors. So far, only little is known about the function of the Mediator complex in BCa. The aim of this study was therefore to investigate the role of MED1 in BCa as a prognostic biomarker and a biomarker of disease progression.
Methods:
The protein expression of MED1 was assessed by immunohistochemistry (IHC) on tissue microarrays from 224 patients: benign urothelium n = 31, non-muscle invasive BCa (pTis, pT1) n = 72, and muscle invasive BCa (pT2-T4) n = 121. Comprehensive clinicopathological information including follow-up were available. Quantification of MED1 protein expression was evaluated by the semiquantitative image analysis program Definiens.
Results:
MED1 expression significantly decreased during BCa progression from benign urothelium to advanced BCa. Muscle invasion, the crucial step in BCa progression, was associated with low MED1 protein expression. Accordingly, decreased MED1 expression was found in primary BCa samples with positive lymphonodal status and distant metastases. Furthermore, cancer-specific survival was significantly worse in the group of low MED1 expression.
Conclusion:
Our findings show that the downregulation of MED1 is associated with muscle invasion, metastatic spread, and shorter overall survival in BCa.
Insights
MED1 protein expression decreases as bladder cancer (BCa) progresses. Low MED1 levels correlate with muscle invasion, metastasis, and poorer survival, indicating its potential as a prognostic biomarker for BCa.
Area of Science:
- Oncology
- Molecular Biology
- Biomarker Discovery
Background:
- Bladder cancer (BCa) is a frequent malignancy with significant mortality.
- The Mediator complex regulates gene transcription and is implicated in various cancers.
- MED1's role in BCa is largely unexplored, despite its known functions in other cancers.
Purpose of the Study:
- To investigate MED1's role in bladder cancer.
- To evaluate MED1 as a prognostic biomarker for BCa.
- To assess MED1's utility as a biomarker for disease progression in BCa.
Main Methods:
- Immunohistochemistry (IHC) was used to assess MED1 protein expression.
- Tissue microarrays from 224 patients with benign urothelium and BCa (non-muscle invasive and muscle invasive) were analyzed.
- Quantitative image analysis was employed to evaluate MED1 expression levels.
Main Results:
- MED1 expression significantly decreased with BCa progression from benign to advanced stages.
- Low MED1 protein levels were associated with muscle invasion, lymph node positivity, and distant metastases.
- Patients with low MED1 expression exhibited significantly worse cancer-specific survival.
Conclusions:
- MED1 downregulation is linked to aggressive features of bladder cancer, including muscle invasion and metastasis.
- Decreased MED1 expression serves as a significant prognostic indicator for poorer survival in BCa patients.
- MED1 represents a potential biomarker for predicting disease progression and outcomes in bladder cancer.