Neoplasia—all you wanted to know but were afraid to ask

Abstract

This presentation will give a brief outline of three important aspects of neoplasia: the role of genetic defects, prediction of tumour behaviour and how tumours cause morbidity and mortality. Neoplasia is a process of uncontrolled new growth of tissue resulting in a space-occupying neoplasm (or tumour). All cells within a neoplasm are thought to be clones of a single cell, which developed genetic defects that are then passed on to further generations of cells. Neoplasia can therefore be seen as a genetic disease. Particularly in human diagnostic pathology, prediction of the behaviour of a tumour is critical for providing a correct prognosis and treatment options. This has traditionally been performed by assessing the morphological characteristics of the tumour in a biopsy specimen. Combined with other clinico-pathological information, this allows staging or grading of the tumour. Whilst this is still an important part in the overall assessment of the likely behaviour of a tumour, many additional laboratory tests (on the neoplasm itself or on serum/plasma samples) are now also available as an adjunct. The ways in which tumours cause clinical signs are diverse; as well as acting as space-occupying lesions, they can release a number of factors that can lead to adverse effects in sites well removed from the mass.