Overexpression in 35% of primary tumors, 30% of lymph node metastases, 70% of recurrences
THURSDAY, April 2, 2015 (HealthDay News) — The mediator subunit MED15 appears to be involved in head and neck squamous cell carcinoma (HNSCC), according to a study published in the April issue of The American Journal of Pathology.
Zaki Shaikhibrahim, Ph.D., from the University Hospital of Bonn in Germany, and colleagues examined the role of MED15 in HNSCC. They performed immunohistochemistry for MED15 on 324 tissue samples. MED15 knockdown was also performed, followed by proliferation and migration assays, as was transforming growth factor-β-1 (TGF-β1) treatment followed by MED15 analysis.
The researchers found that MED15 was overexpressed in 35, 30, and 70 percent of primary tumors, lymph node metastases, and recurrences, respectively, compared with no or low expression in benign tumors. In primary tumors from patients who developed recurrences, MED15 overexpression correlated with elevated mortality rates and was seen at the highest frequency in oral cavity or oropharyngeal tumors. There was a correlation for MED15 expression between primary tumors and corresponding lymph node metastases. TGF-β activity in tissues was associated with MED15; TGFβ activation led to increased MED15 expression and decreased pSMAD3 on MED15 knockdown.
“Taken together, our results implicate MED15 in HNSCC and hint that MED15 overexpression is a clonal event during HNSCC progression,” the authors write. “MED15 may serve as a prognostic marker for recurrence and as a therapeutic target.”
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