Fig. 4.

Specific markers of mesenchymal cells are overexpressed in both CD44⁺/CD24^−/low-MS cells and letrozole-treated patient tumors. (A) For the flow sort and cancer MS profile datasets, heat map of previously associated mesenchymal genes in a review by Lee et al. (31) (genes in bold, significant with P < 0.01; the entire set of mesenchymal-associated proteins from the review that we could map to specific genes in our dataset are represented). (B) Protein expression of vimentin and pan-cytokeratin (CK) in a patient tumor after letrozole treatment. (C) Immunofluorescence analysis of vimentin (red) and pan-cytokeratin (green) after chemotherapy. Yellow arrows mark double-positive cells, whereas red and green arrows mark vimentin and CK positive epithelial cells, respectively. (D) MMP2mRNA levels in tumors before and after letrozole. (P values in B and C by paired t test).