Oral cavity squamous cell carcinoma and Waldeyer ring squamous cell carcinoma PDL-1 expression: A large, retrospective, single institution site series on head and neck squamous cell carcinoma, looking at the relationship with morphology, human papilloma virus and p16.

Abstract

TPS119 Background: The most frequent type of epithelial malignancy in oral cavity and Waldeyer's ring (WR) is squamous cell carcinoma (SCC). Patients with Head and Neck SCC (HNSCC) show reduced levels of CD3+, CD4+, and CD8+ T cells compare to healthy controls. SCCs with a higher number of intra-tumoural CD4+ and CD8+ lymphocytes are associated with better prognosis. Programmed death receptor ligand (PD-L1 ) is present on the surface of neoplastic cells in SCC. T cells harbour inhibitory receptors (the so-called immune checkpoints) such as PD-1. Activation of this immune checkpoints results in T cell deactivation. The PD-1/PDL-1 interaction provokes an immunosuppressive effect which allows the tumour to evade immune destruction. However, WR SCCs present some diversities comparing to oral cavity SCC: younger age, frequent neck LN metastasis, often cystic, distinct morphology: often undifferentiated and solid (nonkeratinizing basal cell morphology), better prognosis, often HPV+, often p16+, an increased number of CD56+ cytotoxic NK. Methods: We have a series of 90 cases of epithelial malignancy in oral cavity and Waldeyer's ring (WR)Squamous cell Carcinoma, registered for Ethics IRAS number for Translational study with Immunohistochemistry; Real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR); Fluorescence in Situ Hybridisation (FISH); Next Generation Sequencing; Digital Imaging scanning and visualising microscopy. The Study will show the relationship of PDL-1 expression with morphology, Human Papilloma Virus (HPV) infection and p16 expression, answering if the oral cavity SCC and Waldeyer's Ring SCC express PD-L1 in the same way.