Gene Expression Strategies for Developing Blood-Based Screening Diagnostics for Colorectal Cancer

Abstract

The N-myristoyltransferase isozymes, NMT1 and NMT2, have attracted growing interest in disease research, especially in the context of cancer. They are responsible for catalyzing the lipidic modification of N-terminal glycine and lysine residues of target proteins, altering their function, localization, and molecular interactions. Recent studies, including those from our laboratory have established NMT1 and NMT2 as key molecules in oncogenesis. In fact, our previous work has demonstrated the overexpression of NMT2 in the peripheral blood mononuclear cells (PBMCs) of colorectal cancer (CRC) patients and individuals with adenomatous polyps (AP). CRC is classified as one of the most treatable cancers, however, it remains a leading cause of cancer related deaths. Without effective screening tests, CRC is often able to progress into advanced stages. While the stool-based tests and colonoscopy remain the primary methods for CRC detection, they often have low adherence rates due to inconvenience and the invasiveness of the colonoscopy. Therefore, a convenient, more accurate, and cost-effective screening test for CRC holds the potential to improve both the quality of life and survival outcomes for patients. Building on our previous studies focused on developing an NMT2-based blood test, this study aimed to assess the gene expression of the NMT isozymes and their upstream target, MetAP2, to build upon previous IHC findings. To ensure accurate gene expression normalization, I validated four candidate reference genes in PBMCs collected from individuals with various colorectal pathologies and no evidence of disease. Using these reference genes, I assessed expression differences among pathophysiological groups and observed meaningful group differences based on effect size. Importantly, the choice of normalization strategy influenced the results, highlighting the importance of accurate reference gene selection.Canadian Cancer SocietyMaster of Science in Bioscience, Technology and Public Polic