The interaction between squamous cell carcinoma (SCC) cells and the tumor microenvironment (TME) plays a major role in cancer progression. Therefore, understanding the TME is essential for the development of cancer therapies.We used four (primary and metastatic) head and neck (HN) SCC cell lines and cultured them on top of or within 5 matrices (mouse sarcoma-derived Matrigel®, rat collagen, human leiomyoma-derived Myogel, human fibronectin, and human fibrin). We performed several assays to study the effects of these matrices on the HNSCC behavior, such as proliferation, migration, and invasion, as well as cell morphology, and molecular gene profile.Carcinoma cells exhibited different growth patterns depending on the matrix. While fibrin enhanced the proliferation of all the cell lines, collagen did not. The effects of the matrices on cancer cell migration were cell line dependent. Carcinoma cells in Myogel-collagen invaded faster in scratch wound invasion assay. On the other hand, in the spheroid invasion assay, three out of four cell lines invaded faster in Myogel-fibrin. These matrices significantly affected hundreds of genes and a number of pathways, but the effects were cell line dependent.The matrix type played a major role in HNSCC cell phenotype. The effects of the ECMs were either constant, or cell line dependent. Based on these results, we suggest to select the most suitable matrix, which provides the closest condition to the in vivo TME, in order to get reliable results in in vitro experiments.

This study clarified the injury characteristics and occurrence of associated injuries in patients with assault-related facial fractures. Data from 840 assaultrelated facial fracture patients were included; demographic factors, facial fracture type, associated injuries, alcohol use, and injury mechanisms were recorded. Assault mechanisms most often included combinations of different mechanisms (57.5%) and resulted in the victim falling (50.1%). The perpetrator was most commonly a stranger (52.5%) and acted alone (57.7%). A total of 123 patients (14.6%) had associated injuries, with the most common being traumatic brain injury. Associated injuries occurred most frequently in patients with combined fractures of the facial thirds (24.2%) and upper third fractures (42.9%). The most significant differentiating factors for associated injuries were the number of perpetrators, falling, the use of an offensive weapon, and if the events of the assault remained unknown. In adjusted logistic regression analyses, statistically significant associations with associated injuries were found for age (odds ratio (OR) 1.05, 95% confidence interval (CI) 1.03-1.07; P < 0.001), falling due to the assault (OR 2.87, 95% CI 1.49-5.50; P = 0.002), and upper third facial fractures (OR 6.93, 95% CI 2.06-23.33; P = 0.002). A single punch also caused severe injuries and should therefore not be overlooked, as this can be as dangerous as other assault mechanisms.