a, Expression level of genes identified as overexpressed in 4T1-T compared with 4T1-E in the primary tumours of patients with different disease subtypes (edges of the box are the 25th and 75th percentiles and error bars extend to the values q 3 + w(q 3 − q 1 ) and q 1 − w(q 3 − q 1 ), in which w is 1.5 and q 1 and q 3 are the 25th and 75th percentiles, which is also true for b, d, and e, ANOVA P < 0.0001). b, Expression level of the same genes in disease-free survivors and patients with relapse to the lung (rank-sum P < 0.01). c, For each gene that was identified in the screen, a prognostic value was calculated using three different datasets. One consisted of gene expression measurements in three patient-matched basal tumour and metastasis pairs (patients A1, A7, and A11). Here genes were classified as correlated with progression if expression was higher in each of the metastases and negatively correlated if expression was higher in each of the primaries. The other two datasets consisted of primary tumour gene-expression profiles with matched outcomes. For the UNC254 patient dataset, the site of relapse was not available and genes were deemed positively correlated with progression if they had significant (Cox P < 0.05) relapse-free survival hazard ratios greater than 1, and negatively correlated if these ratios were significant (Cox P < 0.05) and less than 1. As the UNC855 dataset also had site of relapse information, here both relapse-free and lung relapse-free survival (RFS and LRFS) hazard ratios were used to classify genes as positively or negatively correlated with progression based on the same criteria that were used for the UNC254 data. d, Expression level of ASNS in the primary tumours of patients with different disease subtypes (ANOVA P < 0.0001). e, Expression level of ASNS in the primary tumours of patients with non-specific relapse and relapse to the lymph node, bone, brain, liver, or lung compared with expression levels in patients without relapse to each corresponding site (rank-sum P < 0.005). f, Analysis of ASNS in three additional sets from patients with breast cancer (MDACC, METRABIC, and TCGA). Shown are survival plots and relevant statistics (Cox P < 0.01). g, Analysis of ASNS in the TCGA Pan-Cancer expression data. Shown are survival plots and relevant statistics for the ten non-breast solid tumours represented in the dataset (Cox P < 0.05 for colon, squamous head and neck, renal clear cell, and endometrial cancers). h, Analysis of ASNS across all tumours represented in the TCGA Pan-Cancer dataset (Cox P = 1.5 × 10−12).