Breast Cancer Breakthrough

breast cancer

Recently, researchers at Lawrence Berkeley National Laboratory have developed the first clinically-relevant mouse model of human breast cancer, as part of successfully expressing functional estrogen receptor positive (ER+) adenocarcinomas.  The tumors that have been generated in this system bear a strong resemblance to the class of tumors that can be found among most women with breast cancer, in particular those whose cancer proves treatment-resistant.  Such a model could prove itself a powerful tool for testing therapies for aggressive E+ breast cancers, as well as for studying the biology and etiology of luminal cancers.

In the study, xenografts of the cell line “184AA3” consistently formed human estrogen receptor positive (ER+) luminal breast tumors in mice.  These account for nearly 80 percent of all newly-diagnosed breast cancers each year, and more women end up dying from treatment-resistant luminal breast cancer than all other types combined.  The researchers say that their discovery of the conditions under which 184AA3 cells generate luminal tumors serves as an important step towards defining and ultimately overcoming the obstacles of properly diagnosing this common (and often fatal) form of breast cancer.

ER+ luminal breast cancers are adenocarcinomas, meaning that they start in cells with a secretory function, in this instance the milk-producing luminal cells of the breast.  Despite the presence of ER+ luminal tumors and their nearly-30-percent conversion to treatment resistance, there aren’t very many models of this cancer subtype available for the development of drugs.  In addition, models that do exist have the questionable clinical relevance in that they generate tumors that look and behave a lot more differently than human tumors.

To develop their xenograft model of ER+ luminal breast cancer, the researchers looked at several cell line models of breast cancer progression.  These allowed an exploration of earl cancer transformative events, in turn providing insight into the initiation and ultimate progression of tumors.  They eventually focused on a collection of cell lines known as the “184” series, which were created in the 1990s from women going through reduction mammoplasty.

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