Breast cancer is the most common cancer worldwide, and in Europe, with one in eight women globally diagnosed with breast cancer during their lifetime and more than 464,000 new cases diagnosed in 2012 alone (29% of female cases and 13% of the total cancer cases).
Scientific research has dramatically improved diagnosis and treatment for this indication. This has led to continuous improvement of overall survival, especially for patients under the age of 75 where survival rates have increased by 2% annually over the past 20 years.
Today’s science assumes, that the development of cancer is a multi-step process of genetic changes in the genes responsible for regulating the growth of cells. These genes are in each cell’s nucleus and regulate the activity of each cell. In healthy tissue, the cells in our bodies replace themselves through an orderly process of cell growth: healthy new cells take over as old ones die out. Over time, mutations can “switch on” certain genes and “switch off” others. Cells changed in this way may show abnormal cell growth and cell features leading to formation of tumors and infiltration of tumors into surrounding tissue. The ability to infiltrate and spread into healthy tissues distinguishes a malignant tumor from a benign tumor.
Based on these insights, it has been commonly accepted that breast cancer cannot be considered as one single disease. Instead, it has become evident that different molecular subtypes of breast cancer require a different treatment approach. Thus a careful separation of different subtypes is the key to a successful treatment strategy.