Cell lines are immortal cell cultures that are used extensively in biomedical research. Some key uses of cell lines include studying basic cell biology, testing drug toxicity, cancer research, virology studies, and gene therapy. Common cell lines include HeLa cells from cervical cancer tissue and MCF-7 cells from breast cancer tissue. Cell lines are also important in the production of vaccines, antibodies, and other biological products through recombinant protein expression in cultured cells. Respiratory and pancreatic beta cell lines have applications in research on inflammation, diabetes, and other diseases.