Breast cancer : A new preclinical research tool

Because of their similarity to patient tumors, these models are an exceptional tool for testing the efficacy of new drugs, adapting treatments to tumor characteristics, unraveling resistance to certain treatments, and as a result limiting the need for clinical trials in patients. Institut Curie and Inserm medical oncologists, surgeons, pathologists and biologists collaborated on this work on mouse models which can now be extended to other types of cancers. The 25 breast tumor models are described in a study published in the 1 July 2007 issue of Clinical Cancer Research.

To help clinicians in their search for more effective treatments, Marie-France Poupon and her team in Institut Curie Inserm Unit 612 “Genotoxicology, signaling and experimental radiotherapy” have developed the largest ever series of human breasts cancers grafted into mice. This six-year study would not have been successful without close collaboration between Institut Curie and Inserm medical oncologists, surgeons, pathologists, and biologists.

These breast cancer xenografts in mice reproduce the genetic, genomic, and histological characteristics of the patient-derived tumor tissues. So they recapitulate features of the original tumors, such as overexpression of HER2 receptors, absence or presence of estrogen receptors, mutation of P53, and react identically to chemotherapy.

Twenty-five models of breast tumors in mice of different biological profiles have been established. These models are an excellent preclinical research tool and can be used to test the efficacy of new drugs and novel therapeutic combinations, as well as analyze the response to treatment and adapt it to the tumor characteristics. This will help in the design of clinical trials and hasten the development of new treatments.

This work is continuing within the framework of the creation of a Preclinical Investigation Laboratory in the Translational Research Department at the Institut Curie, with a view to extending this series of tumor models to other types of cancers, such as pediatric cancers, melanoma, lung cancer, ovarian cancer, and cancers of the bronchi, prostate, and colon.

Breast cancer

Breast cancer is the most frequent cancer in women and affects one in ten women in the developed world. Every year in France there are 42 000 new cases. Between 1980 and 2000, the number of cases increased by almost 60%, largely as a result of increasingly efficient detection and because people are living longer. Breast cancer is most commonly detected in women aged between 50 and 69 years of age (half of all cases), but can occur at any age, albeit very rarely before the age of 25.

Mortality has declined because of earlier detection and improved treatments combining surgery, radiotherapy, and chemotherapy, depending on the tumor characteristics. When the diagnosis is made early enough, conservative surgery is possible: the tumor is removed and the breast conserved. When the tumor is larger, or is accompanied by extensive precancerous lesions, it is sometimes essential to remove the breast (mastectomy).