Recent studies showed that human papillomavirus (HPV) integration contributes to the genomic instability seen in HPV-associated head and neck squamous cell carcinoma (HPV-HNSCC). However, the epigenetic alterations induced after HPV integration remains unclear. To identify the molecular details of HPV16 DNA integration and the ensuing patterns of methylation in HNSCC, we performed next-generation sequencing using a target-enrichment method for the effective identification of HPV16 integration breakpoints as well as the characterization of genomic sequences adjacent to HPV16 integration breakpoints with three HPV16-related HNSCC cell lines. The DNA methylation levels of the integrated HPV16 genome and that of the adjacent human genome were also analyzed by bisulfite pyrosequencing. We found various integration loci, including novel integration sites. Integration loci were located predominantly in the intergenic region, with a significant enrichment of the microhomologous sequences between the human and HPV16 genomes at the integration breakpoints. Furthermore, various levels of methylation within both the human genome and the integrated HPV genome at the integration breakpoints in each integrant were observed. Allele-specific methylation analysis suggested that the HPV16 integrants remained hypomethylated when the flanking host genome was hypomethylated. After integration into highly methylated human genome regions, however, the HPV16 DNA became methylated. In conclusion, we found novel integration sites and methylation patterns in HPV-HNSCC using our unique method. These findings may provide insights into understanding of viral integration mechanism and virus-associated carcinogenesis of HPV-HNSCC.

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Background/Aim: We evaluated the impact of FosL1, a member of the activated protein-1 family, on the pathways leading to regional metastasis of head and neck squamous cell carcinoma (HNSCC). Materials and Methods: We examined the influence of small interfering RNA (siRNA) and short heparin RNA (shRNA) mediated knockdown of FosL1 on cell migration, invasion, and proliferation in vitro as well as on regional metastasis in vivo. The prognostic significance of FosL1 was also analyzed using the Kaplan-Meier plotter using data from an HNSCC patient database. Results: Down-regulation of FosL1 inhibited cell migration, invasion, and proliferation in vitro, decreased the incidence of regional metastases, and prolonged the survival of mice in vivo. We also determined that HNSCC patients with higher expression levels of FosL1 had a significantly shorter survival time than those with low expression of FosL1. Conclusion: FosL1 plays a crucial role in promoting cell migration, invasion, and proliferation in HNSCC.Head and neck squamous cell carcinoma (HNSCC) patients often have advanced disease with cervical lymph node metastases at the time of diagnosis (1), resulting in poor prognosis despite advances in treatment modalities. Furthermore, treatment failure is often associated with locoregional recurrence in HNSCC patients. The presence of cervical lymph node metastasis is reported as one of the reliable prognostic factors for the survival of patients with HNSCC (2). Therefore, it is necessary to elucidate the mechanisms of cervical lymph node metastases to develop new treatments to improve the survival outcomes of patients with HNSCC.We previously reported that JunB, a member of the AP-1 family, regulates metastatic pathways by promoting cell invasion and migration of HNSCC (3). Thus, AP-1, which forms heterodimers with proteins of the Fos family, the Jun family, musculoaponeurotic fibrosarcoma (Maf), and activating transcription factor (ATF) (4, 5), plays crucial roles in regulating cellular processes such as proliferation, differentiation, death, and survival induced by growth factors, cell-matrix interactions, infections, cytokines, and stresses (6, 7). The Fos family of proteins and c-Jun have also been reported to induce tumorigenesis and metastasis (3,4,(8)(9)(10).These studies led us to characterize the regional metastatic potential in vivo using 14 different HNSCC cell lines in an orthotopic nude mouse model. We performed an upstream and key node analysis using whole-gene microarray data of these lines to determine key molecules associated with the regional metastatic potential of HNSCC. As we identified FosL1 as one of the key molecules associated with the regional metastatic potential of HNSCC, we examined the impact of FosL1 knockdown on cell migration in vitro, as well as cervical lymph node metastasis in vivo, to test the hypothesis that FosL1 could be the key molecule regulating the pathways associated with neck lymph node metastasis in HNSCC.

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Orbital infection mainly develops as a complication of sinusitis, and often disturbs the functions of the eye by raising orbital pressure due to abscess formation. We herein report on a case of an intraorbital abscess in the upper-lateral part of the orbit following acute sinusitis occurred in a 59-year-old male. At presentation, the sinusitis itself had already been improved and the abscess did not have contact with frontal or the ethmoid sinuses. A quick and correct diagnosis of sinusitis followed by orbital infection is essential. An urgent surgical drainage along with an adequate use of antibiotics is required to preserve the eyesight.