B2M and neoplasm: Accordingly, these findings address the following clinical implications: (a) β2M must play a far-reaching function than just a housekeeping gene or the role on stabilisation and presentation of MHC class I molecule in cells; (b) β2M may act as an effective growth-promoting factor to facilitate tumour progression, invasion, and migration in OCSCC; and (c) increased synthesis and/or release of β2M by an elevated serum or urine β2M concentration may become one of important prognostic factor and survival predictors in OCSCC.