In contrast to suppressors known to be prone to mutation, i.e., p53 and PTEN, to our knowledge, CYTL1 harbors rare loss-of-function variants.17,31 These features of CYTL1 as a novel tumor suppressor may be very important not only for our understanding of tumor suppressors but also for the development of new antitumor approaches. This evidence concerns the gene PTEN and neoplasm.