COL9A2 and breast angiosarcoma: In addition, previous studies showed the aberrant other collagen gene expressions (COL10A1, COL15A1, COL22A1, COL9A2 [5] and COL3A1, COL1A2 [7]), not COL6A1, COL6A2, COL6A3, and COL1A1 genes as our study, in patients with BA.