COL3A1 and fibrosarcoma: Notable, among these fusions are in-frame fusions of the collagen genes (exon 6 COL1A2, exon 20 COL1A2 and exon 35 COL3A1) with exon 2 of PDGFB in tumors of the H2 fibrosarcoma cluster which was associated with extracellular matrix and G-protein coupled receptor signaling pathways.