Comparative Characterisation of Subcutaneous, Intraperitoneal and Intrabursal OVCAR3 Models

OVCAR3 cells are widely used to establish animal models of high-grade serous ovarian cancer (HGSOC) via subcutaneous (SC), intraperitoneal (IP), and intrabursal (IB) routes. However, direct comparisons of tumour development across these implantation routes are limited. This study compared the establishment, progression, dissemination and histological characteristics of SC, IP and IB OVCAR3 xenografts in female athymic nude mice over defined route-specific assessment periods. Tumour development was evaluated using semi-quantitative tumour scoring, histological assessment, nuclear morphometry and immunofluorescence staining for PAX8, WT1 and Ki67. IP and IB routes achieved 100% engraftment whereas SC implantation achieved engraftment in 15 of 18 animals. IP produced rapid carcinomatosis by Week 2, IB produced localised ovarian growth before contralateral spread, and SC produced confined stromal-encapsulated tumours. Mechanical confinement in the IB niche increased intratumoural density (1087 cells/mm²) and compressed single-cell nuclear area (22 µm²) compared to IP/SC models. Histological and immunofluorescence assessment demonstrated tumour expression of PAX8, WT1 and Ki67 across the three models, with route-associated differences in tumour organisation and staining distribution. Nuclear morphometric measurements varied among the models, although the between-route differences were not statistically significant. Together, these findings define the principal characteristics and progression patterns of three commonly used OVCAR3 implantation models and provide a practical framework for selecting the route and experimental timeframe most appropriate to the aims of future studies.