Fig. 1

Distribution of the DNA index value of 2994 neuroblastoma tumors belonging to Italian Neuroblastoma Register [2]. The DNA index percentage value for each clinical stage is reported in the upper panel (red color). On the left, green value are referred to the 1.0 for diploid cells, 1.5 and 2.00 for hyperdiploid cells. A DNA index of 1.50 is more frequent in tumors of patients who are younger than 18 months for all stages but not for stage 4 patients who have a peak of 43% DNA of diploid cells. Tumors of patients over 18 months of age primarily show a DNA diploid tumor cells with a peak (62%) of tumor cells in stage 4. Stage 4S is not represented because occurs in patients under 12 months of age, by definition