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USF Alum Turned Professor Leads Breast Cancer Research


Christina Tzagarakis-Foster began her academic career at the University of San Francisco as an undergraduate biology major. Now, the assistant professor has returned to her alma mater to teach the same topic and to lead a group of students in promising breast cancer research.

Tzagarakis-Foster began teaching at USF in fall 2005 and brought with her a desire to learn more about a gene that effectively stops or slows down the uncontrolled growth of breast cells. She first started researching the gene while a University of California, San Francisco post-doctoral student studying reproductive endocrinology.

Known as DAX-1, the gene was first noticed because of its role in sex determination in humans. More recent experimental data, however, have also shown that the gene interacts with various proteins, or receptors, such as those that bind with estrogen. When DAX-1 interacts with these proteins, it functions as a brake by stopping or slowing down the activation of gene expression caused by these receptors.

In the case of breast cancer, estrogen receptors cause many genes to activate or turn on, which leads to uncontrolled growth of breast cells. If DAX-1 is introduced in these breast cancer cells, they do not proliferate as rapidly. Tissue samples from breast cancer patients have shown that while DAX-1 was present in the patients' non-cancerous breast tissue, it was absent in two-thirds of the cancerous samples.

"It makes sense that if you lose a brake to a system, cells can grow out of control," she said.

Tzagarakis-Foster's lab work currently focuses on understanding DAX-1's role in breast cancer as well as its place in human development. By researching its human development role, Tzagarakis-Foster hopes to fully understand the molecular mechanism behind the gene and how the gene fully works.

"We know the end product, what we don't know is how it gets there," Tzagarakis-Foster said.

This knowledge, in turn, could help in understanding DAX-1's role in breast cancer. In fact, Tzagarakis-Foster's lab is one of only a small number of labs around the country researching this. Yet unlike labs at other universities, Tzagarakis-Foster conducts hers with no doctoral students. Instead, she has one master's student and four undergraduates, a situation she knows some researchers might find intimidating. She, however, does not.

"If you train people well and get them excited by it, they can do it, and they can do it just as well as a grad student can," Tzagarakis-Foster said.