CA9 and neuroblastoma: We also report that, in a subcutaneous xenotransplant NB model the growth index of NB tumor nodules, the rate of GD2 positive malignant cells and the cell proliferation index are highly correlated with the expression level of two genes of our malignant set, MCM2 and carbonic anhydrase 9 (CA9), validating these genes as possible novel targets for NB therapy.