Conclusions: Cancer biology, a moveable feast

The increasing amount of knowledge we are acquiring has improved our understanding of cancer biology and the way we classify tumours in clinical practice in order to provide a personalised, more effective treatment. Tumours include a large number of different types of abnormal growths. The main division, into benign and malignant, is based on the ability of a neoplastic lesion to produce metastases during the natural course of the disease. Malignant tumours are a heterogeneous group of lesions, which are brought together under the generic name of cancer and its synonymous. Although we recognize a tumour as malignant intuitively, to be able to define choose, and describe what are the basic characteristics common to all the types of cancers is challenging and it could be argued whether it is actually possible and/or correct to attempt it. Recent breakthroughs in biology have certainly improved our knowledge of cancer and the treatment available. However, we are also constantly unveiling new layers of complexity that need development of new tools in order to be dealt with.