To analyze the characteristics of perioperative mortality (POM) in oral maxillofacial head and neck cancer patients.

A retrospective study was adapted for head and neck cancer patients who were treated and had POM in the department of oral maxillofacial & head and neck oncology in Shanghai Ninth People′s Hospital from Jan 1999 to Dec 2019. Demographic information, disease characteristic and clinical records were collected. The factors of POM were classified into surgical complication, medical complication, mixed complication (surgical and medical) and personal complication. SPSS 17.0 software was used to analyze the cause composition for POM under different condition.

55 patients were included: 39 were male, and 16 were female. A total of 12 patients had a smoking history. Furthermore, 28 patients had general comorbidities. 20 underwent preoperative radiotherapy and 9 received preoperative chemotherapy. Squamous cell carcinoma was the most frequent pathological diagnosis in 37 patients. A total of 9 patients had tumors in the maxilla and skull base. In addtition, 4 patients had POM preoperatively, 1 patient had POM within the operation, and 50 patients had POM postoperatively. The leading causes of death were as follows: rupture of the carotid artery was the most frequent (8), and the surgical complication of pulmonary infection was the main medical complication (6). Pulmonary infection and hemorrhage were regarded as the main mixed complication (4). Two patients had POM due to personal complications. The higher the American Society of Anesthesiologists (ASA) score, the higher the proportion of medical factors in POM (P＝0.039).

The composition of POM in oral maxillofacial- head and neck cancer (OMHNC) patients was complicated. Carotid artery rupture was the most common and fatal surgical complication, especially for those who underwent preoperative radiotherapy. Pulmonary infection was the most frequent medical complication, and those who had a higher ASA grade tended to have more complication.

To investigate the role of long non-coding RNA double homeobox A pseudogene 9 (DUXAP9) in head and neck squamous cell carcinoma (HNSCC) and to evaluate the expression level, molecular function and mechanism of DUXAP9 in HNSCC cells.

Differential expression of lncRNAs between normal and tumor tissues in HNSCC tissues were screened using lncRNA microarray, the expression level of DUXAP9 in HNSCC tissues and its relationship with prognosis were analyzed in the TCGA database. The expression levels of DUXAP9 in HNSCC tissues and cell lines were detected using qRT-PCR. The function in HNSCC cells after DUXAP9 silencing was evaluated using the CCK-8 assay, wound healing assay, Transwell migration assay and subcutaneous xenograft assay in nude mice. Changes in the transcription and translation of epithelial-mesenchymal transition (EMT)-related proteins in head and neck squamous cell carcinoma cells after DUXAP9 silencing were detected using qRT-PCR and Western blot.

lncRNA microarray results showed that, compared to adjacent normal tissues, DUXAP9 was abnormally upregulated in HNSCC tissues. Analysis from TCGA database showed that, compared to HNSCC patients with low DUXAP9 expression, HNSCC patients with high DUXAP9 expression had poorer survival. The relative expression of DUXAP9 in HNSCC tissues and 4 HNSCC cell lines increased compared to paired adjacent normal tissues as detected using qRT-PCR. Silencing DUXAP9 significantly inhibited the proliferation, migration and expression of EMT-related genes in HNSCC cells. The silencing of DUXAP9 significantly inhibited subcutaneous tumorigenesis of the HNSCC cell line CAL27 in nude mice.

Silencing DUXAP9 significantly inhibited the proliferation of HNSCC cells and subcutaneous xenografts in nude mice. DUXAP9 may mediate the migration of head and neck squamous cell carcinoma cells via the EMT pathway.