Immunopathological evaluation in oral squamous cell carcinomas: a series of cases

Evaluation of the expression of programmed death ligand-1 (PD-L1) is considered an eligibility criterion of patients with oral squamous cell carcinoma (OSCC) for anti-PD-L1 immunotherapeutic treatment. However, the evaluation of other components of the tissue microenvironment, such as tumor infiltrating lymphocytes (TILs), is considered important in assessing the response to immunotherapy and should be considered. In this study, 4 cases of OSCC were classified according to the tissue microenvironment and the immunotherapeutic perspectives are discussed. The profile of cases included adaptative immune resistance (TILs high, PD-L1+, low CD4+ and high CD8+), immunological ignorance (TILs low, PD-L1−, low CD4+ and CD8+), intrinsic induction (low TILs, PD-L1+, low CD4 and CD8+), and immunogenicity (TILs high, PD-L1−, high CD4+ and CD8+). This analysis highlights the importance of understanding the vast immunological microenvironment that OSCC can present and the relationship between the prognosis of the patients studied.