PIWI proteins are a subclass of Argonout proteins which have an important role on PIWI interacting RNA (piRNA) mechanisms. piRNAs are the novel class of small non-coding RNAs which regulate genetic and epigenetic regulations via transposon silencing. However, first studies about PIWI proteins and piRNAs focused on the development of germline stem cells; the similarities between stem cells and cancer cells caused cancer researchers to observe the relationship between PIWI protein/piRNA complex and cancer cells. This letter indicates researches which were identified the potential of PIWI proteins in various cancers.
