Traditional tumour markers such as carcinoembryonic antigen (CEA) that have been used for screening gastrointestinal neoplasia for many years are not specific. However, these markers are useful after diagnosis to monitor progress of the disease and recurrence. New biomarkers are constantly being developed to identify individuals with risk of cancer for early detection, to determine prognosis, to detect recurrence, to predict drug responses and to monitor response to treatment. There are several issues involved in the discovery of biomarkers and their development for clinical applications. This article provides a basic overview of the classes of biomarkers, the current status of molecular profiling and discusses the opportunities as well as challenges ahead to improve biomarker development.
Biological Markers ; overview ; Malignant Neoplasms ; development aspects ; Recurrence

Whenever an unexpected neuropsychiatric disorder arises suddenly in a person of good previous mental health after a new drug of any kind has been taken it is reasonable to suspect a drug-induced reaction. The suspected medication should then be stopped. Adverse reactions to drugs are known to account for a considerable amount of neuro-psychiatric disorder, which is likely to increase as new and more potent drugs are introduced into clinical practice.
Mental disorders ; overview ; Drug-induced ; seconds ; Adverse reactions