PROM1 and neoplasm: Besides the expression of unique CD markers such as CD44, CD24, and CD133, the capacity to express biomarkers like drug‐efflux pumps (e.g., ATP‐binding cassette (ABC)), some enzymes such as aldehyde dehydrogenase (ALDH) and transcription factors (e.g., OCT‐4, SOX‐2) CSCs could be distinguished from the entire cells within the tumor.4