Phenotypic plasticity promotes lymph nodes metastasis and drug resistance in lung squamous cell carcinomas.

Background: Phenotypic plasticity (PP) is a major promoter of tumor metastasis and drug resistance. Nevertheless, the molecular features and clinical significance of phenotypic plasticity in lung squamous cell carcinomas (LSCC) remained largely unexplored. Methods: Phenotypic plasticity-related genes (PPRG) and clinical information of LSCC were downloaded from the cancer genome atlas (TCGA). The expression profiles of PPRG were compared between patients with and without lymph node metastasis. The prognostic signature was constructed, and survival analysis was performed based on phenotypic plasticity. Immunotherapy responses, chemotherapeutic drugs and targeted drug responses were investigated. In addition, the results were verified in an external cohort. Results: Patients with and without lymph node metastasis exhibited significantly different genomic characteristics of phenotypic plasticity. Enrichment analysis showed that PP was strongly associated with cell responses and cell contraction. Survival analysis demonstrated that PPRG could serve as independent prognostic factor for overall survival. The phenotypic plasticity-related signature successfully divided patients into high- and low-PP score groups. Patients with low-PP scores were more sensitive to PD-L1, Cisplatin, Gefitinib, Obatoclax. Mesylate, Paclitaxel, Sorafenib and Vinorelbine (all p < 0.05). While, patients with low-PP scores were more sensitive to Axitinib and Camptothecin (all p < 0.05). Consistent with the results from TCGA, the external cohort validated the above findings. Conclusions: Our study revealed that phenotypic plasticity may be involved in the lymph node metastasis in LSCC through regulating cell responses and cell contraction. Evaluation of phenotypic plasticity will assist clinicians in making treatment strategies.