COL4A1 and neoplasm: The amplicon detected on chromosome 13 in tumor 39 (Figure 3A) contained contiguous amplified clones covering a region of about 2.5 Mb at 13q32-34 that included TNFSF13B (a ligand of the tumor necrosis factor superfamily), and collagen type IV genes (COL4A1 and COL4A2).