Development of an in vitro microfluidic model to study the role of microenvironmental cells in oral cancer metastasis.

Metastasis occurs when cancer cells leave the primary tumour and travel to a secondary site to form a new lesion. The tumour microenvironment (TME) is recognised to greatly influence this process, with for instance the vascular system enabling the dissemination of the cells into other tissues. However, understanding the exact role of these microenvironmental cells during metastasis has proven challenging. Indeed, in vitro models often appear too simplistic, and the study of the interactions between different cell types in a 3D space is limited. On the other hand, even though in vivo models incorporate the TME, observing cells in real-time to understand their exact role is difficult. Horizontal compartmentalised microfluidic models are a promising new platform for metastasis studies. These devices, composed of adjacent microchannels, can incorporate multiple cell types within a 3D space. Furthermore, the transparency and thickness of these models also enables high quality real-time imaging to be performed. This paper demonstrates how these devices can be successfully used for oral squamous cell carcinoma (OSCC) metastasis studies, focusing on the role of the vascular system in this process. Conditions for co-culture of OSCC cells and endothelial cells have been determined and staining protocols optimised. Furthermore, several imaging analysis techniques for these models are described, enabling precise segmentation of the different cell types on the images as well as accurate assessment of their phenotype. These methods can be applied to any study aiming to understand the role of microenvironmental cell types in cancer metastatic dissemination, and overcome several challenges encountered with current in vitro and in vivo models. Hence, this new in vitro model capable of recapitulating important aspects of the cellular complexity of human metastatic dissemination can ultimately contribute to replacing animal studies in this field.

Oral Squamous Cell Carcinoma Frequency in Young Patients from Referral Centers Around the World.

Oral squamous cell carcinoma (OSCC) commonly affects older patients; however, several studies have documented an increase in its incidence among younger patients. Therefore, it is important to investigate if this trend is also found in different geographic regions. The pathology files of diagnostic and therapeutic institutions from different parts of the globe were searched for OSCC cases diagnosed from 1998 to 2018. Data regarding the sex, age, and tumor location of all cases, as well as the histologic grade and history of exposure to risk habits of cases diagnosed as OSCC in young patients (≤ 40 years of age) were obtained. The Chi-square test was used to determine any increasing trend. A total of 10,727 OSCC cases were identified, of which 626 cases affected young patients (5.8%). Manipal institution (India) showed the highest number of young patients (13.2%). Males were the most affected in both age groups, with the tongue and floor of the mouth being the most affected subsites. OSCC in young individuals were usually graded as well or moderately differentiated. Only 0.9% of the cases occurred in young patients without a reported risk habit. There was no increasing trend in the institutions and the period investigated (p > 0.05), but a decreasing trend was observed in Hong Kong and the sample as a whole (p < 0.001). In conclusion there was no increase of OSCC in young patients in the institutions investigated and young white females not exposed to any known risk factor represented a rare group of patients affected by OSCC.

The Expression of Glutaminases and their Association with Clinicopathological Parameters in the Head and Neck Cancers.

BACKGROUND: The increased glutamine metabolism is a characteristic feature of cancer cells. The interconversion between glutamine and glutamate is catalyzed by two glutaminase isoforms, GLS1 and GLS2, which appear to have different roles in different types of cancer. We investigated for the first time the protein expression of GLS1 and GLS2, and their correlation with advanced clinicopathological parameters in head and neck cancers. METHODS: Consecutive slides from a tissue microarray comprised of 80 samples ranging from normal to metastatic were stained immunohistochemically for GLS1, GLS2, HIF-1α or CD147. Following analysis by two expert pathologists, we carried out a statistical analysis of the scores. RESULTS: GLS1 and GLS2 were found to be upregulated at the protein level in head and neck tumours compared to normal tissues, and this increased expression correlated positively (GLS1) and negatively (GLS2) with tumor grade, indicating a shift of expression between GLS enzyme isoforms based on tumor differentiation. Increased expression of GLS1 was associated with high CD147 expression, and elevated GLS2 expression was associated with both high CD147 and high HIF-1α expressions. The correlation of the GLS1 and GLS2 with HIF-1α or CD147 was strongly associated with more advanced clinicopathological parameters. CONCLUSION: The increased expression of GLS1 and GLS2 may be explored as a new treatment for head and neck cancers.

Plasma cell mucositis related to qat chewing: a report of 2 cases and review of the literature.

Plasma cell mucositis is a rare, benign mucosal condition with characteristic histological features of a dense polyclonal plasmacytic infiltrate. A variety of mucosal sites are affected and the presentation varies from a cobblestone to an intensely erythematous, lobulated appearance. Idiopathic cases are well documented and it has been attempted to define the entity as a hypersensitivity reaction, however reports show inconsistencies. The last two decades have highlighted an emerging association between qat (khat) chewing and plasma cell mucositis. This report provides a review of the most pertinent literature and describes two cases intimately related to qat chewing, whereby resolution occurred upon qat cessation. One case requiring systemic steroidal therapy due to severe symptoms. This highlights the need for an increased awareness amongst clinicians of a potential aetiological link between qat and plasma cell mucositis, emphasises the benefit of qat cessation and the scenarios whereby systemic steroidal therapy should be considered.