Fig. 7

MB3W1 cells comprise a faithful Group 3 model. a. Upper panel: FISH analysis of MB3W1 cells revealed a clear amplification of the MYC oncogene (green signal) as a hallmark of Group 3 tumors (in red: CEP8). Middle panel: FISH on chromosome 17 shows (consistent with the patient’s karyogram) tetraploidy of the ERBB2 gen (red signal) and an unbalanced gain of chromosome 17q (green signal of the chromosome enumeration probe 17p11.1-17q11.1). Lower panel: Immunohistochemical staining of xenotransplanted tumor specimen revealing accumulation of p53 protein. b. Heatmap, illustrating analysis of a set of 22 marker genes previously validated for MB sub-grouping. Strong clustering of genes regulated in Group 3 MB is observed. No significant differences in gene expression were detected in RNA derived from early passages (<5 passages) or late passages (>20 passages)