Several factors may explain why not all signatures showed consistent prognostic value across the independent PRECOG dataset: (1) lack of equivalent TCGA versus PRECOG cancer type (example: CESC - Cervical squamous cell carcinoma and endocervical adenocarcinoma; n = 5 signatures); (2) gene absent in PRECOG (example: ADAMTS9-AS1 in PRAD-1064.6.3.N.2.95.26.1.2.1); (3) the validation process relied on stringent statistical thresholds (|Meta-Z| > 3.09 or < −3.09, p < 0.001) to identify significant poorer or better prognosis, respectively. Here, ADAMTS9 is linked to cancer.