Gastric cancer (GC) represents a notable amount of morbidity and mortality worldwide. Understanding the molecular basis of CG will offer insight into its pathogenesis in an attempt to identify new molecular
biomarkers to early diagnose this disease. Therefore, studies involving small non-coding RNAs have been widely explored. Among these, PIWI-interacting RNAs (
piRNAs) are an emergent class that can play important roles in
carcinogenesis. In this study, small-
RNA sequencing was used to identify the global
piRNAs expression profile (piRNome) of
gastric cancer patients. We found 698
piRNAs in gastric tissues, 14 of which were differentially expressed (DE) between
gastric cancer (GC), adjacent to
gastric cancer (ADJ), and non-
cancer tissues (NC). Moreover, three of these DE
piRNAs (piR-48966*, piR-49145, piR-31335*) were differently expressed in both GC and ADJ samples in comparison to NC samples, indicating that the
tumor-adjacent tissue was molecularly altered and should not be considered as a normal control. These three
piRNAs are potential risk
biomarkers for GC, especially piR-48966* and piR-31335*. Furthermore, an in-silico search for mRNAs targeted by the differentially expressed
piRNAs revealed that these
piRNAs may regulate genes that participate in
cancer-related pathways, suggesting that these small non-coding RNAs may be directly and indirectly involved in gastric
carcinogenesis.