Abstract
There is an increasing incidence of GI cancers as per the Cancer Registry Data. In such a situation, it is essential to evaluate the patient by standard investigational tools like clinical examination and endoscopy which help in establishing the diagnosis. Determination of tumour markers is useful not only in diagnosis and prognosis of cancer but also monitoring of cancer treatment. Tumour markers in GI oncology include oncofoetal proteins, hormones, enzymes and cancer antigens. Recent advances include application of tumour marker level determination combined with newer radiological and functional imaging such as FDG PET - CT.