GDF6 exhibits bidirectional dysregulation: downregulation in 23 cancers (e.g., GBM, BRCA) and upregulation in 7 subtypes (e.g., KIRC, PAAD), correlating with advanced stages (KIRP, STAD) and poor survival (OS/DFS in KIRP, STAD, MESO). The gene discussed is GDF6; the disease is glioblastoma.