An example of a DE gene is Dysadherin (FXYD4), a cell membrane glycoprotein involved in modulating cell–cell adhesion, whereof its expression level is correlating with metastatic behavior in for example breast cancer and head and neck cancer [73, 74, 75], expressed at higher abundance in subgroups 2 and 3 and lower abundance in subgroup 1 (i.e., PN group) of our analysis. The gene discussed is FXYD4; the disease is head and neck cancer.