Table 1.

Factors Underpinning Immune Evasion in Head and Neck Squamous Cell Carcinoma.

Mechanisms	References
Inhibition of chemotactic recruitment of antigen-presenting cells and effector cells	Leibowitz et al. 2013; Li et al. 2015; Lei, Xie, et al. 2016; Nguyen et al. 2016
Overactivation of the suppressor populations and metabolic insufficiency in effector cells	Costa et al. 2013; Davis et al. 2016; Scharping et al. 2016
Engagement of the immune checkpoint receptor signaling and suppression of effector function	Lyford-Pike et al. 2013; Li et al. 2015; Bauman et al. 2017; Kansy et al. 2017
Alterations to autophagy	Baginska et al. 2013; Lei, Kansy, et al. 2016
Cancer stem cell-mediated immunosuppression	Hu et al. 2016; Lee et al. 2016