CTC phenotypes representing tumor-initiating markers comprised one or more markers, such as aldehyde dehydrogenase (ALDH), CD44, or CD133, indicating a tumor-initiating cell (TIC) phenotype, which could act as an independent factor for reduced OS and disease-free survival (DFS), as reported in a recent study (Poruk et al., 2017). This evidence concerns the gene PROM1 and neoplasm.