Tumour markers in pediatric solid tumours

Tumour marker as a term generally refers to developmentally regulated proteins which are expressed in or from neoplastic tissues. Traditionally these proteins were protein or carbohydrate molecules, which were expressed in the fetus during the developmental period, thus these were also known as ‘oncofetal antigens’. In the present era the term ‘tumour marker’ has acquired a broader sense and implies any molecule or marker that aids in diagnosis or treatment of a specific tumour. An ideal tumour marker is a molecule of tumour cell origin released by the tumour cells in quantities easily detectable in the circulation or body fluids of the host and proportional to the tumour burden and is not present in the non-tumour bearing hosts.