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Gastrointestinal endoscopy has made great progress during last decade. Diagnostic accuracy can be enhanced by
better training, improved dye-contrast techniques method, and the development of new image processing
technologies. However, diagnosis using conventional endoscopy with white-light optical imaging is essentially
limited by being based on morphological changes and/or visual attribution: hue, saturation and intensity,
interpretation of which depends on the endoscopist's eye and brain. In microlesions in the gastrointestinal tract, we
still rely ultimately on the histopathological diagnosis from biopsy specimens. Autofluorescence imaging system has
been applied for lesions which have been difficult to morphologically recognize or are indistinct with conventional
endoscope, and this approach has potential application for the diagnosis of dysplastic lesions and early cancers in the
gastrointestinal tract, supplementing the information from white light endoscopy. This system has an advantage that
it needs no administration of a photosensitive agent, making it suitable as a screening method for the early detection
of neoplastic tissues. Narrow band imaging (NBI) is a novel endoscopic technique which can distinguish neoplastic
and non-neoplastic lesions without chromoendoscopy. Magnifying endoscopy in combination with NBI has an
obvious advantage, namely analysis of the epithelial pit pattern and the vascular network. This new technique allows
a detailed visualization in early neoplastic lesions of esophagus, stomach and colon. However, problems remain;
how to combine these technologies in an optimum diagnostic strategy, how to apply them into the algorithm for
therapeutic decision-making, and how to standardize several classifications surrounding them. 'Molecular imaging'
is a concept representing the most novel imaging methods in medicine, although the definition of the word is still
controversial. In the field of gastrointestinal endoscopy, the future of endoscopic diagnosis is likely to be impacted
by a combination of biomarkers and technology, and 'endoscopic molecular imaging' should be defined as
"visualization of molecular characteristics with endoscopy". These innovations will allow us not only to locate a
tumor or dysplastic lesion but also to visualize its molecular characteristics (e.g., DNA mutations and
polymorphisms, gene and/or protein expression), and the activity of specific molecules and biological processes that
affect tumor behavior and/or its response to therapy. In the near future, these methods should be promising
technologies that will play a central role in gastrointestinal oncology.
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