B2M and cancer: The first studies of cancer cells with upregulated or downregulated β2M expression were initiated two decades ago; however, to date, few articles have shown that a decrease in the cell surface concentration of β2M is associated with a poor prognosis in malignant cases of oral cavity squamous cell carcinoma (OCSCC) (Prime et al, 1987; Feinmesser et al, 2004).