Establishment of primary cell cultures from canine mammary gland malignant tumours: a preliminary study.

INTRODUCTION: Canine mammary gland cancer (CMGC) is the most common neoplastic condition in bitches and is often fatal. There are limited treatment options for CMGC. Primary cell cultures from mammary tumours are promising preclinical in vitro models in which to study personalised treatment approaches. This preliminary study aimed to establish primary cell cultures from two canine mammary gland neoplasms: a common solid adenocarcinoma and a rare carcinosarcoma. MATERIAL AND METHODS: Tumour masses were collected from a 13-year-old and a 16-year-old German shepherd. Tumour cells were isolated by mechanical disaggregation and enzymatic digestion of masses with 0.05% type IV collagenase. Primary cell cultures were validated by immunocytochemistry for specific markers including mucin 1 (MUC1), cytokeratin 8 and 18 (CK8/18) and Kiel 67 (Ki-67). RESULTS: Primary cell cultures achieved confluency by day 7 of culture, displaying polygonal cellular morphology. Cultures of both cell types exhibited strong positivity for MUC1 of >99% and high Ki-67 proliferation activity of 43.1% ± 0.5% in the solid adenocarcinoma-derived positive cells and 87.9% ± 2.7% in the carcinosarcoma-derived positive cells. Positivity was observed for CK8/18 of 98.1% ± 0.3% in cells derived from solid adenocarcinoma and 31.6% ± 1.5% in cells derived from carcinosarcoma. CONCLUSION: With further characterisation, the primary cell cultures established in this study can be expected to show considerable potential as foundational in vitro models for cancer research.