Fig. 1: Notch3 and EGFR levels correlate in TNBC primary samples.

a Upper panel: summary of the NOTCH3-EGFR and NOTCH1-EGFR gene expression levels correlation obtained by an in silico analysis from two TNBC tissue arrays (GSE76124 and GSE31519). Lower panels: representative graphs showing correlation between NOTCH3 (left) or NOTCH1 (right) and EGFR gene expression levels from GSE31519 dataset in a cohort of 579 TNBC patients. In both graphs, each dot corresponds to one patient and the expression value of NOTCH3, NOTCH1, and EGFR is given in log2 scale after normalizing data with justRMA algorithm normalization. The X–Y axis represent NOTCH3 (left) or NOTCH1 (right) and EGFR (both) expression levels, respectively. The index Pearson’s R indicated expresses the linear relation between paired samples and P-values were calculated using Student’s T-test, as described in Material and Methods section. b Upper panel: heatmap representing the protein levels of EGFR, Notch3, and Notch1 obtained by immunohistochemical analysis (IHC) in a cohort of 18 TNBC patients. The colors represent positive (red) or negative (blue) protein levels according to protein expression cutoff (see Materials and Methods section). Lower panel: summary of the Notch3-EGFR and Notch1-EGFR protein expression levels correlation showing percentage of each category calculated on the precedent category of patients. c Pattern of immunostaining in two different cases of TNBC. In case 1 (upper panels), there is a strong and diffuse staining of neoplastic cells both for EGFR (A) and Notch3 (B), whereas Notch1 is completely negative (C). In case 2 (lower panels), the neoplastic cells are negative for both EGFR (D) and Notch3 (E), whereas Notch1 (F) shows a weak positivity in about 20% of the cells