Cancer immunology relates to the cellular and molecular interactions between the tumor and the immune system. Various components of the immune system may sometimes enhance or hinder tumor progression: Chronic inflammation for example can lead to cancer initiation by mediating genomic instability and epigenetic reprogramming. Established cancers usually induce an anti-inflammatory environment, which in turn stimulates tumor growth, metastasis and therapy resistance. On the other hand, cancer cells undergo molecular changes that can be recognized by the immune system and result in the destruction of transformed cells. Clinical as well as experimental evidence strongly suggest that this immune surveillance is a potent safeguard mechanism against cancer and consequently implies that tumorigenesis requires immune evasion. The mechanism that define the tumor promoting as well as limiting activities of the immune system are being revealed and culminate in the rapid development of immunotherapies. Distinct types of immunotherapies, including monoclonal antibodies, cancer vaccines, adoptive T-cell transfer or unspecific immune-modulation (e.g. with interferon or interleukin) have been clinically tested. The most exciting breakthrough in recent years has been achieved with immune-checkpoint inhibitors, which target regulatory pathways of T-cells (CTLA-4 or PD-1) to increase anti-tumor immune responses. These therapies elicited astonishing durable responses in advanced aggressive diseases as non-small cell lung cancer or melanoma. However, response rates to immunotherapy in different cancers remain heterogeneous and current research focuses on the regulatory mechanisms of immune responses in the tumor microenvironment. Understanding the underlying mechanisms will aid to identify possible combinational therapeutic approaches to provide a survival advantage for a greater number of patients.
Did you know that patients with pharmacological or pathological immunosuppression are at increased risk of diverse cancers, of both cancers related to infections (e.g. cervical or liver) but also infection-unrelated cancers as in the lung or kidney?