Diagnostic value of 18F-FDG-PET to predict the tumour immune status defined by tumoural PD-L1 and CD8+tumour-infiltrating lymphocytes in oral squamous cell carcinoma

• Published in: British journal of cancer 2020-05, Vol.122 (11), p.1686-1694
• Main Authors: Togo, Maria, Yokobori, Takehiko, Shimizu, Kimihiro, Handa, Tadashi, Kaira, Kyoichi, Sano, Takaaki, Tsukagoshi, Mariko, Higuchi, Tetsuya, Yokoo, Satoshi, Shirabe, Ken, Oyama, Tetsunari
• Format: Article
• Language: English
• Subjects: 631/67/327; 631/67/580/1884; 692/53/2421; Apoptosis; Biomedical and Life Sciences; Biomedicine; Cancer Research; CD8 antigen; Cold; Drug Resistance; E-cadherin; Epidemiology; Glucose transporter; Hypoxia-inducible factor 1; Hypoxia-inducible factor 1a; Hypoxia-inducible factors; Immune checkpoint; Immune status; Lung cancer; Lymphocytes; Medical diagnosis; Molecular Medicine; Oncology; Oral cancer; Oral squamous cell carcinoma; PD-1 protein; PD-L1 protein; Phenotypes; Positron emission tomography; Prognosis; Squamous cell carcinoma; Tumors
• ISSN: 0007-0920; 1532-1827
• DOI: 10.1038/s41416-020-0820-z

Background Lately, immune checkpoint proteins, such as programmed death 1 (PD-1) and its ligand-1 (PD-L1), have garnered attention as a new target in oral squamous cell carcinoma (OSCC). Reportedly, fluoro- d -glucose (FDG)-uptake alteration by anti-PD-1 antibody treatment depicts the response in patients with lung cancer. This study aims to elucidate the correlations between tumour immune status, clinicopathological factors, 18 F-FDG-uptake and cold tumour phenotypes as low PD-L1 expression/low CD8 + tumour-infiltrating lymphocytes (TILs) in OSCC. Methods We performed immunohistochemical analysis of PD-L1, hypoxia-inducible factor 1 A (HIF-1A), glucose transporter type 1 (GLUT1), CD8, E-cadherin and Ki-67 on 59 operable OSCC samples. We assessed the correlations between these factors and preoperative 18 F-FDG-uptake, clinicopathological characteristics and prognosis. Results Low expression of PD-L1 in OSCC correlated with cancer aggressiveness, poor prognosis, high 18 F-FDG-uptake with HIF-1A/GLUT1 and low E-cadherin expression and low CD8. Cold tumour phenotypes as low PD-L1 tumour cells and low stromal CD8 correlated with the poor prognosis, high 18 F-FDG-uptake and E-cadherin suppression. Furthermore, the high level of preoperative 18 F-FDG-uptake in OSCC was an independent predictor of the cold tumour immune status. Conclusions 18 F-FDG-uptake is an independent predictor of cold tumour in OSCC. 18 F-FDG-PET imaging could be a promising diagnostic tool to estimate tumour immune status.