According to histological subtypes, as shown in Table 2, MGP, GATA3, and TRPS1 were found to be positive in 86.5% (64/74), 62.2% (46/74), and 98.6% (73/74) of squamous cell carcinomas (SqCC), 83.3% (15/18), 22.2% (4/18), and 94.4% (17/18) of spindle cell carcinomas (SpCC), 92.5% (37/40), 32.5% (13/40), and 100% (40/40) of metaplastic breast carcinomas with mesenchymal differentiation (MBC-MD), and 100% (8/8), 37.5% (3/8), and 87.5% (7/8) of fibromatosis-like metaplastic carcinomas (FMC). This evidence concerns the gene MGP and fibromatosis.