The interplay of immune components and ECM in oral cancer

We report that in Oral Squamous Cell Carcinoma (OSCC), extracellular matrix (ECM) plays a vitally important role in defining the characteristics of cancer vs. normal, as it is a compartment with significant enrichment of known OSCC biomarkers, and the number of genes constituting ECM are more prominently upregulated in OSCC than almost all the rest of the cancer types. This is probably due to the constant exposure of oral cavity to external stimuli, resulting in the ECM remodeling, which further is a key player in tumor invasion. While we showed ECM molecules alone could well distinguish oral cancer from normal tissue samples, a significant portion of these predictive ECM molecules, share the same transcriptional regulator, NFKB1, a master regulator of immune response. We further studied the level of involvement of the immune system in OSCC, and found that the immune composition in OSCC is distinctly different from the other cancer types. OSCC has a higher level of infiltration of adaptive immune cells, including B cell, T cell and neutrophil, compared with other cancer types, while a lower level of infiltration of innate immune, including macrophage and monocyte. Previous studies have revealed the roles of ECM and immune system in OSCC development, and our study showed that ECM plays a very prominent role in OSCC, subject to the complex microenvironment in oral cavity, particularly the immune system profile, and our association analysis revealed it is likely the interactions between ECM and immune cells that define the highly invasive property of OSCC.