IL13RA2 and breast cancer: Based on this analysis as well as on validation in a subset of these cell lines by real-time PCR and Western blotting, we found that IL13Rα2 overexpression is exclusively enriched in a subset of basal-B breast cancer cells that are highly metastatic to the lungs (MCF10CA1a, MDA-MB-436, BT549, SUM159, and MDA-MB-231-LM2-4175) [23, 31, 33, 34] but not in any of the luminal or basal-A subtype cells (Additional file 4: Figure S3 and Additional file 5: Figure S4).