Rejuvenation of piRNAs in emergence of cancer and other diseases

Abstract piRNAs (PIWI-interacting RNAs) are a predominant class of small non-coding RNA (~ 26–32 nucleotides in length) mostly involved in maintaining self-renewal of germline cells. They exert their effect primarily on transposable elements either by posttranscriptional regulation or epigenetic mechanisms. Further studies revealed aberrant expression of PIWI proteins/piRNAs across various cancers to be correlated with tumor grade and patient survivability rate. Thus, piRNAs opened up a new avenue highlighting their effective use as biomarkers for early and specific diagnosis of disease. In this chapter, we emphasize on the regulatory role of piRNAs in modulating cancer and other diseases as well as the challenges one might encounter while using it for therapeutic intervention. Further, piRNAs have the potential to act as a critical factor in mediating the convergence between the features of developmental biology and cancer biology by balancing their expression and maintaining cellular homeostasis.