As determined by immunohistochemistry, the bigger tumor masses with expectedly high Cav-1 expression were characterized by increased staining with marker of proliferation Ki-67 (MKI67, also known as MIB-1) and cluster of differentiation 31 (CD31), two markers predictive of cell mitosis and vascularization, respectively (Fig. 6C). The gene discussed is PECAM1; the disease is neoplasm.