COL6A1 and glioblastoma: Furthermore, relevance between COL6A1 and ITGA5 (TCGA GBM: Spearman r = 0.598, p < 0.001; Rembrandt GBM: Spearman r = 0.455, p < 0.001) was higher than ITGAV (TCGA GBM: Spearman r = 0.208, p = 0.009; Rembrandt GBM: Spearman r = 0.267, p < 0.001) (Figure 7D,E).