SIX1 protein expression selectively identifies blastemal elements in Wilms tumor.
BACKGROUND: Wilms tumor (WT) is the most common renal neoplasm in children. Histologically, most WTs consist of three tissue elements: blastema, epithelium, and stroma. Some cases also show diffuse or focal anaplastic features. Previous studies have shown that a predominance of blastemal cells in post-chemotherapy WT specimens is associated with a poor clinical course. However, there is currently