COL1A1 and cancer: In this study, differential gene expression analysis revealed a prospective CTC signature consisting of five genes (BCAR1, COL1A1, IGSF3, RRAD, and TFPI2) whose expression (a) was robustly enriched across all CTC-derived samples (Figure 4c) and (b) was associated with poorer disease-free survival using the pan-cancer TCGA dataset (Figure 4d).