In vivo xenograft model of ovarian cancer

Twenty female nude mice (Huafukang Biosciences, Beijing, China) were randomly divided into two groups and injected with either OVCAR3-YWHAE-MOCK or OVCAR3-YWHAE-H ovarian cancer cells. Approximately 100 µL of cell suspension containing 1 × 10⁷ cells was injected subcutaneously into the armpit of the right forelimb of each mouse. Tumour progression and overall health status of the mice were observed every 3 days, and the diameter of the tumour and the weight of the mice were measured. The tumour volume was calculated using the following formula: V = (a × b²)/2, where (a) represents the largest diameter, and (b) the shortest diameter. On day 7 post-injection, newly formed tumours were detectable; on day 21, the largest tumour was nearly 1 cm in diameter, and the mice had started to show poor health symptoms. The tumour samples were then fixed in 4% paraformaldehyde and embedded in paraffin. Continuous 5 μm-thick sections were cut and analysed using either haematoxylin and eosin or immunohistochemical staining. This animal study was approved by the Institutional Animal Research Committee of China Medical University.