Predicting therapeutic responses in head and neck squamous cell carcinoma from TP53 mutation detected by cell-free DNA

Background: Head and neck squamous cell carcinoma (HNSCC) is an epithelial malignant tumor originating from the oral cavity, oropharynx, nasal cavity, sinuses, nasopharynx, hypopharynx, or larynx. Mutations in TP53 are the most common of all somatic genomic changes in HNSCC, and TP53 mutations are associated with the response to immunotherapy and chemotherapy. Tumor-derived circulating cell free DNA (cfDNA) is a minimally invasive method to determining genetic alterations in cancer. This study aimed to explore the therapeutic responses of patients with HNSCC with TP53 mutation and the accuracy of cfDNA for detecting TP53 mutation.Methods: Information on TP53 mutations, patient survival time, and clinical data in HNSCC were downloaded from The Cancer Genome Atlas database. The difference in immune infiltration between the TP53-mutant group and the wild-type group was compared. We applied the single-sample gene set enrichment analysis method on the transcriptome of HNSCC samples to assess the distribution of immune cell types between the two groups. The chemotherapy response was constructed using the R software package, "pRRophetic". Gene set enrichment analysis was performed based on the TP53 mutation. The next-generation sequencing was executed on cfDNA from nine patients with HNSCC to detect genetic alterations. Tumor biopsy (n=9) was sequenced using the same technique.Results: TP53 was the most frequently mutated gene in HNSCC. The TP53 mutation was related to immune cells and the expression of immune-associated genes. The TP53 mutation group showed lower response to immunotherapy but high sensitivity to some chemotherapies compared with the wild-type group. TP53 was the most frequently mutated gene (6/9; 66.67%) in cfDNA. Only 27.27% of TP53 mutations in tumor tissue were detected outside of cfDNA.Conclusions: TP53 mutation could be used as a specific predictor of treatment response in patients with HNSCC. Using cfDNA to detect the TP53 mutations in patients with HSNCC is a feasible method. The results suggested that the therapeutic response in patients could be predicted by detecting TP53 mutations in cfDNA, and large-scale and prospective studies are needed to validate this hypothesis.