Spatial PD‐L1, immune‐cell microenvironment, and genomic copy‐number alteration patterns and drivers of invasive‐disease transition in prospective oral precancer cohort

Abstract

Background Studies of the immune landscape led to breakthrough trials of programmed death‐1 (PD‐1) inhibitors for recurrent/metastatic head and neck squamous cell carcinoma therapy. This study investigated the timing, influence of somatic copy‐number alterations (SCNAs), and clinical implications of PD‐L1 and immune‐cell patterns in oral precancer (OPC). Methods The authors evaluated spatial CD3, CD3/8, and CD68 density (cells/mm2) and PD‐L1 (membranous expression in cytokeratin‐positive intraepithelial neoplastic cells and CD68) patterns by multiplex immunofluorescence in a 188‐patient prospective OPC cohort, characterized by clinical, histologic, and SCNA risk factors and protocol‐specified primary end point of invasive cancer. The authors used Wilcoxon rank‐sum and Fisher exact tests, linear mixed effect models, mediation, and Cox regression and recursive‐partitioning analyses. Results Epithelial, but not CD68 immune‐cell, PD‐L1 expression was detected in 28% of OPCs, correlated with immune‐cell infiltration, 9p21.3 loss of heterozygosity (LOH), and inferior oral cancer‐free survival (OCFS), notably in OPCs with low CD3/8 cell density, dysplasia, and/or 9p21.3 LOH. High CD3/8 cell density in dysplastic lesions predicted better OCFS and eliminated the excess risk associated with prior oral cancer and dysplasia. PD‐L1 and CD3/8 patterns revealed inferior OCFS in PD‐L1 high intrinsic induction and dysplastic immune‐cold subgroups. Conclusion This report provides spatial insight into the immune landscape and drivers of OPCs, and a publicly available immunogenomic data set for future precancer interrogation. The data suggest that 9p21.3 LOH triggers an immune‐hot inflammatory phenotype; whereas increased 9p deletion size encompassing CD274 at 9p24.1 may contribute to CD3/8 and PD‐L1 depletion during invasive transition. The inferior OCFS in PD‐L1‐high, immune‐cold OPCs support the development of T‐cell recruitment strategies.

Nivolumab for Patients With High-Risk Oral Leukoplakia

“…23,24,40,41 This may be due to deletions encompassing the type I interferon gene cluster, 42 which is often co-deleted with the tumor suppressor CDKN2A, highlighting a key mechanism of immune evasion. 43 In our immunogenomic studies, only pretreat- 44 and associated with an immune-cold signal in OSCC 23 that is enhanced by larger deletions extending to the telomeric band at 9p24.1. 40 We speculate that resistance to the PD-1 inhibitor in this aggressive oral precancerous disease trial may have arisen during ICT…”

“…In our immunogenomic studies, only pretreatment 9p21.3 deletion yielded statistically significant differences: 6 of 10 patients with 9p21.3 deletion in baseline biopsies later developed cancer. We have previously shown that 9p21.3 copy-number loss is generally a focal event in oral precancer and associated with an immune-cold signal in OSCC that is enhanced by larger deletions extending to the telomeric band at 9p24.1 . We speculate that resistance to the PD-1 inhibitor in this aggressive oral precancerous disease trial may have arisen during ICT resulting from increasing 9p deletion size to encompass 9p24.1, leading to low expression of the therapeutic target (PD-L1) and other immune gene depletion .…”

“…23,40,45 PD-L1 is encoded by the CD274 gene, which is located on 9p24.1, close to 9p21, and is often co-deleted in advanced human papillomavirus-negative head and neck squamous cell carcinoma and lung cancers. 42,44…”

“…We speculate that resistance to the PD-1 inhibitor in this aggressive oral precancerous disease trial may have arisen during ICT resulting from increasing 9p deletion size to encompass 9p24.1, leading to low expression of the therapeutic target (PD-L1) and other immune gene depletion . PD-L1 is encoded by the CD274 gene, which is located on 9p24.1, close to 9p21, and is often co-deleted in advanced human papillomavirus–negative head and neck squamous cell carcinoma and lung cancers …”

Oral epithelial dysplasia with lymphocytic immune response: clinicopathological characterisation of 44 cases

“…'Lymphocytic immune response' is more compatible with descriptions of the immune microenvironment in OED, in which high CD3/8+ lymphocyte density may predict better squamous cell carcinoma (SCC)-free survival, particularly in OED that does not express PD-L1. 26 LIR could represent the intra-epithelial/dysplastic counterpart to tumour infiltrating lymphocytes (TIL) well recognised in many cancers, including head and neck SCC, where a minority of patients benefit from PD-1/ PD-L1 blockade. [27][28][29][30][31] Not unsurprisingly, in this cohort one OED with LIR had a focus of invasive SCC with TILs (Figure 9F).…”