Figure 1 shows representative examples of CD133 antigen expression in primary ovarian cancer: Immunoreaction appeared to be present as a diffuse staining of cytoplasm (diffuse cytoplasmic pattern) of tumor cells forming solidly arranged tumors or at the apical/endoluminal surface (apical cytoplasmic pattern) of tumor cells surrounding a lumen. This evidence concerns the gene PROM1 and ovarian cancer.