Objective:To investigate the expression of p21-activated kinase 2 (PAK2) in laryngeal squamous cell carcinoma and its relationship with the clinicopathological characteristics and chemosensitivity of patients.Methods:Transcriptome sequencing (RNA-seq) data for laryngeal squamous cell carcinoma were downloaded from the Cancer Genome Atlas (TCGA) database, and 123 patients were included in the study (12 cases had cancer tissues and normal tissues data, and the remaining 111 only had cancer tissues data). Differential expression of PAK2 in cancer and para-cancer tissues was analyzed by using R software, and the potential function of PAK2 in laryngeal squamous cell carcinoma was investigated by using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database signaling pathway enrichment. A total of 34 patients with primary laryngeal squamous cell carcinoma tissues and corresponding para-carcinoma 34 tissue specimens who underwent surgical resection were retrospectively selected from Chaoyang Central Hospital between April 2016 and June 2021, and 20 cases of normal laryngeal mucosa tissues were selected as the controls. Immunohistochemistry was used to detect the expression of PAK2 in various tissues, and its correlation with clinicopathological factors was analyzed. A total of 35 supraglottic primary laryngeal squamous cell carcinoma patients were retrospectively collected before induction chemotherapy during the same period, including 20 patients sensitive to chemotherapy and 15 patients resistant to chemotherapy. Real-time fluorescence quantitative polymerase chain reaction (qRT-PCR) was used to detect the relative expression level of PAK2 mRNA in cancer tissues.Results:Analysis of TCGA database data showed that PAK2 expression was increased in cancer tissues compared with that in para-cancer tissues ( P = 0.012); KEGG database signaling pathways showed that the high expression of PAK2 in laryngeal squamous cell carcinoma was related to signal transduction pathways, cell cycle, and cancer. Immunohistochemistry showed that the proportion of PAK2 positive in 34 cases of laryngeal squamous cell carcinoma tissues was higher than that in adjacent tissues and normal tissues [58.82% (20/34) vs. 0.03% (1/34), 0 (0/20), all P < 0.001]. There were statistically significant differences in the proportion of PAK2 positive patients stratified with different degrees of differentiation [high differentiation vs. low or middle differentiation: 33.33% (6/18)vs. 87.50% (14/16)], lymph node metastasis [presence vs. absence: 90.91% (10/11) vs. 43.48% (10/23)], TNM staging [stage Ⅲ-Ⅳ vs. stage Ⅰ-Ⅱ: 82.35% (14/17) vs. 35.29% (6/17)] (all P < 0.05), and PAK2 positive patients were not associated with clinical type, tumor size, smoking history, drinking history, and age (all P > 0.05). qRT-PCR showed that the relative expression level of PAK2 mRNA in the chemotherapy-resistant group was higher than that in the chemotherapy-sensitive group (3.89±0.12 vs. 0.78±0.23, P < 0.001). Conclusions:The expression level of PAK2 in laryngeal squamous cell carcinoma tissues is increased, and the high expression of PAK2 is closely related to the malignant clinical characteristics of patients with laryngeal squamous cell carcinoma. The high expression of PAK2 may indicate the insensitivity to traditional chemotherapy regimens, and PAK2 may be a potential gene that targets and regulates the chemosensitivity of laryngeal squamous cell carcinoma.