While overexpression of two of the TFPI1 isoforms, TFPIα and β, in breast cancer cells resulted in increased apoptosis of tumor cells [41,43], a recent microarray analysis of breast cancer cells overexpressing TFPIα or β in vitro resulted in differential expression of many genes involved in cell development, such as cell growth, adhesion, migration, invasion, and apoptosis [42]. This evidence concerns the gene TFPI and neoplasm.