Gene expression analysis approach to establish possible links between Parkinson's disease, cancer and cardiovascular diseases.

Non-communicable chronic diseases have been apparently established as threat to human health, and are currently the world's main killer. Cardiovascular diseases (CVD), cancer, diabetes and neurodegenerative diseases are collectively amounting to more than 60% of non-communicable disease burden across world. Tremendous advancements in healthcare enabled us to fight several health problems primarily infectious diseases. However, this increased longevity where in many cases an individual suffers from several such chronic diseases simultaneously, making treatment complex. Finding whether diseases can coexist in an individual by chance or there exists a possible association between them is vital. Our goal is to establish possible existing link among CVD, cancer and Parkinson's disease (PD) for better understanding of the associated molecular network. In this study, we integrated multiple dataset retrieved from the National Centre for Biotechnology Information's Gene Expression Omnibus database, and took a systems-biology approach to compare and distinguish the molecular network associated with PD, cancer and CVD. We identified 230, 308 and 1619 differentially expressed genes for CVD, cancer and PD dataset respectively using cut off p value<0.5 and fold change>2. We integrated these data with known pathways using Ingenuity Pathway Analysis tool and found following common pathways associated with all three diseases to be most affected; epithelial adherens junction signaling, remodelling of epithelial adherens junctions, role of BRCA1 in DNA damage response, sphingomyelin metabolism, 3- phosphoinositide biosynthesis, acute myeloid leukemia signaling, type I diabetes mellitus signaling, agrin interactions at neuromuscular junction, role of IL-17A in arthritis, and antigen presentation pathways. In conclusion, CVD, cancer and PD appear tightly associated at molecular level.