The Regression of Glioblastoma Multiforme is Time Dependent in the Wild-type Rat Xenograft Model.

One of the most malignant tumors is the brain tumor in the world. Unfortunately, no effective treatment has yet been found for it. Of course, researchers need efficient animal models to find the appropriate treatment. The xenograft model is one of the tumor models in the laboratory. However, the main challenge is the interaction of the animal's immune system with induced-cancer cells so that the immune system finally rejects the tumor. In this study, we investigated how long the immune system needs to reject induced tumors in the xenograft model completely. For this purpose, we studied the animals in three periods (second week, fourth week, and sixth week). We concluded that the immune system does not recognize the induced cancer cells until the second week of the experiment. It results in the growth of cancer cells and the formation of tumors in the animal brain. However, the immune system begins to recognize the tumor mass after the fourth week which leads to a reduction in metastasis and tumor size. Eventually, the immune system completely rejects the formed tumor in the sixth week.