We then employed a factor analysis approach to study H19 expression in our GBM sample cohort (12 glioblastoma tissues, described in ref.21); in this data reduction approach, a large set of correlated variables is mapped to a smaller set of uncorrelated linear combinations (factors) of the original variables along with the relative contributions (loadings) of each variable to each factor. This evidence concerns the gene H19 and glioblastoma.