Epigenetics is the study of heritable molecular determinants that are independent of phenotypic features. The epigenetic features include DNA methylation, histone modifications, non-coding RNAs, and chromatin remodeling. In multicellular organisms, the epigenetic state of a cell is critical in determining its differentiation status and its ability to perform its proper function. These processes are now well recognized as being a substantial factor in tumor progression and metastasis. The process through which epithelial cells acquire mesenchymal features is known as epithelial-mesenchymal transition (EMT). EMT is associated with tumorigenesis, invasion, metastasis, and resistance to therapy in cancer. In the present review, we examine the recent studies that demonstrate the biological role of epigenetics, in particular, DNA methylation, histone modifications, non-coding RNAs, and chromatin remodeling in tumor progression and metastasis by regulating EMT status, and we provide an overview of the current state of knowledge regarding the epigenetics involvement in tumor progression and metastasis. Because epigenetic changes can be reversed, learning more about their biological roles in EMT will not only help us better understand how cancer progresses and spreads, but it will also help us identify new ways to diagnose and treat human malignancy which is currently lacking in the clinical setting.

Insects are by far the most abundant and diverse living organisms on earth and are frequently prone to microbial attacks. In other to counteract and overcome microbial invasions, insects have in an evolutionary way conserved and developed immune defense mechanisms such as Toll, immune deficiency (Imd), and JAK/STAT signaling pathways leading to the expression of antimicrobial peptides. These pathways have accessory immune effector mechanisms, such as phagocytosis, encapsulation, melanization, nodulation, RNA interference (RNAi), lysis, autophagy, and apoptosis. However, pathogens evolved strategies that circumvent host immune response following infections, which may have helped insects further sophisticate their immune response mechanisms. The involvement of ncRNAs in insect immunity is undeniable, and several excellent studies or reviews have investigated and described their roles in various insects. However, the functional analyses of ncRNAs in insects upon pathogen attacks are not exhaustive as novel ncRNAs are being increasingly discovered in those organisms. This article gives an overview of the main insect signaling pathways and effector mechanisms activated by pathogen invaders and summarizes the latest findings of the immune modulation role of both insect- and pathogen-encoded ncRNAs, especially miRNAs and lncRNAs during insect–pathogen crosstalk.