Establishment of Primary Cell Cultures from Canine Oral Melanomas via Fine-Needle Aspiration: A Novel Tool for Tumorigenesis and Cancer Progression Studies

Simple Summary Oral melanomas are the most common oral tumors in dogs. They are usually aggressive, invasive, and bear a poor prognosis. These neoplasms have genetic and biological similarities with human oral melanoma, suggesting the potential use of the dog as a model in comparative studies. Primary two- and three-dimensional cell cultures from spontaneously arising canine oral melanocytic tumors and their nodal metastasis are established in this study, starting from cells sampled by fine-needle aspiration (FNA). This technique could be considered a helpful and less invasive method to collect samples for cell cultures, particularly for cases where surgery cannot be performed or when the owner refuses a surgical approach. This cell culture model contributes to the array of in vitro models, providing valuable tools for characterizing neoplastic cells and investigating the cellular pathways supporting cancer progression and invasion.Abstract Oral melanomas are the most common oral malignancies in dogs and are characterized by an aggressive nature, invasiveness, and poor prognosis. With biological and genetic similarities to human oral melanomas, they serve as a valuable spontaneous comparative model. Primary cell cultures are widely used in human medicine and, more recently, in veterinary medicine to study tumorigenesis, cancer progression, and innovative therapeutic approaches. This study aims to establish two- and three-dimensional primary cell lines from oral canine melanomas using fine-needle aspiration as a minimally invasive sampling method. For this study, samples were collected from six dogs, represented by four primary oral melanomas and five lymph nodal metastases. The cells were digested to obtain single-cell suspensions, seeded in flasks, or processed with Matrigel (R) to form organoids. The cell cultures were characterized through flow cytometry using antibodies against Melan-A, PNL2, and Sox-10. This technique offers a minimally invasive means to obtain cell samples, particularly beneficial for patients that are ineligible for surgical procedures, and enables the establishment of in vitro models crucial for comparative studies in mucosal melanoma oncology. To the best of our knowledge, this is the first work establishing neoplastic primary cell cultures via fine-needle aspiration in dogs.