PI3K pathway mutation predicts an activated immune microenvironment and better immunotherapeutic efficacy in head and neck squamous cell carcinoma

by Selleckchem | Dec 10 2023

Background: PI3K pathway is the most frequently mutated pathway in head and neck squamous cell carcinoma (HNSC), which plays a crucial role in tumorigenesis and progression. In the present study, we aimed to investigate the role of PI3K pathway mutation in clinical prognosis prediction and the relationship with immune microenvironment and response rate to immunotherapy.

Methods: We collected 129 samples with immunotherapy information from MSKCC-2019 cohort as well as 501 and 40 samples from TCGA-HNSC and MD-Anderson non-immunotherapy cohorts, respectively. Somatic mutation data was utilized to characterize the mutational status of the PI3K pathway. Subsequently, we further analyzed the differences in prognosis, immunotherapy response, genomic alterations, functional characteristics, and immune microenvironment between the mutation and wild groups.

Results: The Kaplan-Meier survival curves displayed that PI3K pathway mutation predicted observably prolonged overall survival (OS) in the immunotherapy cohort MSKCC-2019 (p = 0.012) but did not reach statistical significance in the non-immunotherapy cohorts TCGA-HNSC (p = 0.68) and MD-Anderson (p = 0.68). After incorporating several clinicopathologic features such as age, gender, and tumor mutation burden (TMB), the results of multivariate Cox regression analysis also demonstrated that the PI3K pathway mutation could indicate better immunotherapy outcomes in HNSC patients with a hazard ratio (HR) of 0.533 (95% CI: 0.313-0.910; p = 0.021) in the immunotherapy cohort MSKCC-2019, compared with 0.888 (95% CI: 0.636-1.241; p = 0.487) and 1.939 (95% CI: 0.483-7.781; p = 0.351) in the non-immunotherapy cohorts TCGA-HNSC and MD-Anderson. In addition, the results of the subclass mapping (SubMap) and the tumor immune dysfunction and exclusion (TIDE) also consistently suggested that patients in the mutation group are more likely to benefit from immunotherapy. And further studies showed that the mutation group owned significantly higher TMB, activated immune-related pathways, richer abundance of immune cells, and higher expression levels of immunomodulators. To improve the prognosis of the wild group, we identified five relatively sensitive potential drugs for the wild group, including "BMS-536924," "linsitinib," "NVP-TAE684," "PLX-4720," and "clonazepam."

Conclusions: The PI3K pathway mutation status could be considered as a potential biomarker to predict better immunotherapeutic efficacy and clinical outcomes after immunotherapy in HNSC patients.

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**Title:** *PI3K Pathway Mutation Predicts Improved Immunotherapeutic Efficacy and Clinical Outcomes in Head and Neck Squamous Cell Carcinoma Patients*

**Abstract:**
Head and neck squamous cell carcinoma (HNSC) patients exhibit frequent mutations in the PI3K pathway, a phenomenon associated with tumorigenesis and progression. This study assessed the impact of PI3K pathway mutations on clinical prognosis, immune microenvironment, and response to immunotherapy in HNSC. Utilizing samples from MSKCC-2019, TCGA-HNSC, and MD-Anderson cohorts, PI3K pathway mutational status was analyzed. Results demonstrated that HNSC patients with PI3K pathway mutations experienced significantly prolonged overall survival (OS) in the MSKCC-2019 immunotherapy cohort. Multivariate analysis, considering clinicopathologic factors, confirmed the predictive value of PI3K pathway mutations in immunotherapy outcomes. SubMap and TIDE analyses consistently supported the beneficial effect of PI3K pathway mutations on immunotherapy response. Additionally, mutation carriers exhibited higher tumor mutation burden (TMB), activated immune-related pathways, increased immune cell abundance, and elevated expression of immunomodulators. To enhance outcomes for patients with wild-type PI3K pathway, potential drug candidates were identified. In conclusion, PI3K pathway mutation status emerges as a promising biomarker for predicting improved immunotherapeutic efficacy and clinical outcomes in HNSC patients undergoing immunotherapy.