Del11q groups of the Wang data set. Unfiltered PCA plots of the Wang data set (101 NB samples, 7542 genes). The four hierarchical clusters (h-groups) in panels A-C (left) are colour-coded as follows: Green = h1, Orange = h2, Red = h3, Blue = h4. Del11q genetic aberrations in panels A-C (right) are colour-coded as follows: Black = 11q-deletion, off-white = No 11q-deletion, White = Undetermined. A. PCA of all 101 neuroblastoma cases. B. PCA of 74 cases without MNA and Del1p C. PCA of 55 cases of the hierarchical groups h1 and h2 without MNA and Del1p.