We found that ErbB3 colocalizes with the nucleolar markers fibrillarin or the RNA polymerase I subunit RPA40 in all the glioblastoma cell lines analysed although with different intensity of the signal while in MCF-7 ErbB3 appears expressed on the cell surface and in both the nucleus and in the nucleoli of the cells. Here, ERBB3 is linked to glioblastoma.