Evaluation of the Functionality of 4T1 Cell Line in Development of Metastatic Cancer in Balb/c Mice as an Animal Model

Metastasis is an advanced stage of cancer in which tumor cells are removed from the primary tumor and migrate to other areas of the body and develop a new mass by high replication. Animal models could be applied to evaluate metastasis along with a metastatic and appropriate cell line. Carcinoma 4T1 cell line is a metastatic cell line with excessive cell proliferation and invasion up to the liver, lungs, brain and lymph nodes.
By injection of about 5 ´ 105 4T1 cells to BALB/c mice, primary tumor was developed. Rate of tumor growth, survival and other morphologic symptoms were checked and recorded. To study the metastasis process, liver, lung and brain tissues were separated and the pathological status was studied following hematoxylin/eosin dye staining.
Findings: The primary tumor growth was increased significantly. The survival rate in mice with breast cancer was decreased to maximum in 7-8 weeks. Liver and lung tissues were metastatic with necrosis and infiltration of numerous cancer cells while metastasis was not observed in brain tissue.
In this model, high proliferation of cancer cells in mice was in association with a sharp decline in survival rate as well as lung and liver tissues metastasis. Metastasis to the brain cells might be accomplished by injection of more 4T1 cells and presumably occurs in a longer period.