**Breast Cancer Cell Lines, Tumor Classification,**  *In Vitro* **Cancer Models**

**1** 

*USA* 

**Breast Cancer Cell Line Development** 

Inarguably, the development of cell culture and the ability to grow human cells *in vitro* has revolutionized medicine and scientific research. In the nearly sixty years since the first successful culture of immortalized human tumor cells in the lab in 1952, new fields of research have emerged and new scientific industries have been launched. Without cell lines, medicine would not be as advanced as it is today. Modern techniques that allow for manipulation of cell have allowed for a more complete understanding of the of fundamental

Different types of cell lines exist. Lines are maintained as continuous cultures, are established as primary cultures for transient studies, are created as explants of tumor or tissue samples, or cultivated from a single individual cell. Cell lines, especially cancer cell lines, are ubiquitous and are used for everything. By using cell lines, our understanding of cells and genes, how they function or malfunction, and how they interact with other cells has increased the pace of discovery and fundamentally changed how science is conducted. Cell lines have been established as a model of specific disease types. Individual cell lines have been derived from specific disease states and therefore possess specific characteristics of that disease state. Therefore, they are exceptionally useful to gain insight into normal physiology and how that physiology changes with onset of disease. Novel treatments and therapeutic strategies are investigated in cell lines in order to gain a fundamental detailed understanding of how a cell will react. Initial protocols are developed and tested in cell lines prior to use in animal models or testing in humans. This has enormous implications in

The first breast cancer cell line was established in 1958. Today, lines modeling the varied types of breast cancer help to develop targeted therapy and to provide a molecular signature of gene expression. Cell lines of estrogen/progesterone receptor (ER/PR) positive, ER/PR negative, triple negative (ER/PR/Her2), normal mammary epithelium, metastatic disease, and more are so widely used that it is nearly impossible to identify a recent discovery that

Unfortunately, significant shortcomings of the use of cell lines exist. Cell lines are a model system. They do not always predict the outcome in humans and therefore, do not replace use of whole organisms. They are grown and tested in isolation, therefore the influence of neighboring cells or organs is non-existent in cell culture systems. Over time, cells can differentiate resulting in a change in phenotype from the original culture. Cell lines can

basics of cellular and molecular biology and the biological system as a whole.

discovery and reducing unintended side effects.

hasn't used cell line models at some point during development.

**1. Introduction** 

 **and Authentication** 

*University of Medicine and Dentistry of New Jersey* 

Judith C. Keen
