Objectives/Goals: Clinical relevance of preclinical animal models is commonly in question. Herein, we investigated locoregional tumor immune microenvironment (TIME) differences in tumor-bearing murine oral cancer models, unresponsive to traditional immunotherapy, and also developed an oral tumor resection model to ultimately enhance translational relevance. Methods/Study Population: Here, we utilized carcinogen-induced, HPV-negative preclinical oral cancer models. For TIME studies, ROC1 cells were maintained as published. ROC1 tumors were established in the murine flank and oral cavity of wildtype C57Bl/6 mice, and tumor growth kinetics were assessed at each site. At distinct stages of tumor growth, tumors were harvested, as well as their respective corresponding inguinal and cervical tumor-draining lymph nodes (tdLNs). Multiparameter 28-marker spectral flow cytometry was performed to analyze immune cell populations at each site. For tumor resection studies, MOC2 tumors were similarly maintained and established in the oral cavity. MOC2 tumors were accessed via midline transcervical incisions. Upon tumor excision, wounds were closed with multiple interrupted Vicryl sutures. Results/Anticipated Results: We anticipated no differences between heterotopic and orthotopic tumor sites. Both sites displayed an initial period of delayed ROC1 tumor growth followed by rapid progression. Comprehensive analyses revealed low T cell infiltration overall and increases in select myeloid cells (i.e., macrophages and dendritic cells) over time in both models. Other immune cell types, however, generally increased over time in the flank. Differences between corresponding tdLNs further indicate deviating changes in immunosuppressive phenotypes (i.e., regulatory T cells and macrophages) and immune checkpoint marker expression. Additionally, MOC2 oral tumors were successfully resected with no visible remaining tumor. No subsequent healing complications were observed, and tumor recurrence occurred within 1 week post-surgery. Discussion/Significance of Impact: Tissue-specific TIME and tdLN differences may impact antitumor treatment and response. Ability to resect orthotopic tumors allows for modeling of standard-of-care treatment for oral cancer. These studies can enable tailoring of therapeutic strategies and provide insight into model selection and data interpretation from translational studies.

In September 2023, the UK Health Security Agency’s (UKHSA) South West Health Protection Team received notification of patients with Pseudomonas aeruginosa perichondritis. All five cases had attended the same cosmetic piercing studio and a multi-disciplinary outbreak control investigation was subsequently initiated. An additional five cases attending the same studio were found. Seven of the ten cases had isolates available for Variable Number Tandem Repeat (VNTR) typing at the UKHSA national reference laboratory. Clinical and environmental P. aeruginosa isolates from the patients, handwash sink, tap water and throughout the wall-mounted point-of-use water heater (including outlet water) were indistinguishable by VNTR typing (11,6,2,2,1,3,6,3,11). No additional cases were identified after control measures were implemented, which included replacing the sink and point-of-use heater.

The lack of specific recommendations to control for P. aeruginosa within Council-adopted ear-piercing byelaws or national guidance means that a cosmetic piercing artist could inadvertently overlook the risks from this bacterial pathogen despite every intention to comply with the law and follow industry best practice advice. Clinicians, Environmental Health Officers and public health professionals should remain alert for single cases of Pseudomonas perichondritis infections associated with piercings and have a low threshold for notification to local health protection teams.