The PI3K/AKT/mTOR-Signal Transduction Pathway as Drug Target in Triple-Negative Breast Cancer

Background: With 23% of all new tumour cases, breast cancer is the most common cancer among women worldwide, and is the second leading cause of cancer deaths in women after lung cancer. Of more than one million cases of breast cancer diagnosed globally each year, a high percentage is characterized as triple-negative, lacking the oestrogen, progesterone and Her2/neu receptors. Lack of effective therapies, younger age at onset and early metastatic spread have contributed to the poor prognosis and outcomes associated with triple-negative breast cancer. The phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR-pathway plays a critical role in malignant transformation of human tumours and their subsequent growth, proliferation and metastasis. Therefore, this pathway is regarded as an attractive candidate for therapeutic interventions. Several inhibitors targeting different components of this pathway are in various stages of development. This review provides a short overview of the PI3K/AKT/mTOR-signalling network, discusses the rationale for targeting this pathway and summarizes the use of the PI3K/AKT/mTOR-pathway as drug target for triple-negative breast cancer treatment. Conclusion: Drugs interacting with the PI3K/AKT/mTOR-pathway seems to be an attractive therapeutic option in triple-negative breast cancer.