Integrated multi-omics analyses of oral squamous cell carcinoma reveal precision patient stratification and personalized treatment strategies

Oral cavity squamous cell carcinoma (OSCC), a leading subtype of head and neck cancer, exhibits high global incidence and mortality rates. Despite advancements in surgery and radiochemotherapy, approximately one third of patients experience relapse. To improve current targeted and immunotherapy strategies for recurrent OSCC, we conducted multi-omics analyses on pretreatment OSCC samples (cohorts 1 and 2, n = 137) and identified A3A and EGFR, both at the RNA and protein levels, as inversely expressed markers for patient stratification and response prediction. Survival analysis demonstrated that elevated A3A or PD-L1 expression levels correlated to improved responses to anti-PD-1 therapy in patients (cohort 3a, n = 50, IHC). In contrast, high RRAS expression (cohort 4, n = 252, qRT-PCR) was significantly associated with OSCC recurrence. Cell-based experiments revealed that RRAS was involved in radiotherapy and cisplatin resistance through the EGFR/ RRAS/AKT/ERK signaling pathway. In OSCC patient-derived xenograft (PDX) mouse models, treatments with cisplatin and cetuximab (anti-EGFR) effectively reduced tumor size in EGFR-high-derived (#34) but not A3Ahigh-derived (#22) PDX tumors. Our study demonstrated that A3A-high tumors were immune-hot and responsive to anti-PD-1 therapy, whereas EGFR-high tumors exhibited chr.7p11.2 gains and DNA repair alterations. Additionally, RRAS-high tumors were associated with OSCC recurrence via AKT and ERK phosphorylation and demonstrate improved clinical outcomes with cetuximab therapy (cohort 3b, n = 49, IHC). This study emphasizes the significance of A3A and EGFR expression levels in OSCC patient stratification and precision therapy, suggesting the use of anti-PD-1 or anti-EGFR treatments, respectively based on these biomarkers. Furthermore, RRAS emerges as a novel prognostic marker for local recurrence.