Expression of cell polarity protein scribble differently affects prognosis in primary tumor and lymph node metastasis of breast cancer patients

We evaluated the relationship between the immunohistochemically determined expression of the cell polarity protein scribble to prognosis in different environments of estrogen receptor (ER) expression and epithelial-to-mesenchymal transition (EMT).

We immunohistochemically evaluated the expression level of scribble in primary tumors and lymph node metastases of 225 node-positive breast cancer patients who had received chemotherapy. We then evaluated metastasis-free survival (MFS) in the absence or presence of ER and the EMT-related protein vimentin.

Among patients with ER–positive tumors, patients with low scribble expression in the primary tumor had a significantly shorter MFS than patients with high scribble expression (p = 0.0225). Furthermore, among patients with vimentin-negative tumors, patients with low expression of scribble in the primary tumor had significantly shorter MFS than patients with high expression of scribble (p = 0.0463). In contrast, among patients with vimentin-positive tumors, patients with high expression of scribble in the primary tumor had significantly shorter MFS than patients with low expression of scribble (p = 0.0343). Moreover, among patients with ER–negative tumors, patients with high expression of scribble in lymph node metastases showed significantly higher expression of E-cadherin in metastases (p = 0.0407) and had significantly shorter MFS than patients with low expression of scribble (p = 0.0064).

The prognostic significance of cell polarity depended on the ER expression and EMT. Furthermore, the preservation of cell polarity in metastases was associated with mesenchymal-to-epithelial transition and worse prognosis. Cell polarity promotes the diversity of metastasis in combination with malignancy grade in breast cancer patients.