Angiogenesis in superficial esophageal squamous cell carcinoma: magnifying endoscopic observation and molecular analysis.

Observations of esophageal squamous cell carcinoma using magnifying endoscopy have now been carried out extensively and, as a result, it has become clear that the morphology of the microvessels evident at the tumor surface reflects the depth of tumor invasion. In M1 and M2 cancer, the surface microvasculature reveals dilation and elongation of the intrapapillary capillary loops (IPCL). However, at this stage, some immature capillaries resembling IPCL also arise inside the tumor and, therefore, the view of the microvasculature should be described as one showing 'intermixing of modified IPCL and IPCL-like immature capillaries (IPCL-like abnormal capillary)'. As cancer invades into the muscularis mucosa (M3 or deeper), an obviously dilated and irregularly branched tumor-specific vasculature, more accurately described as 'neovasculature', can be observed. From our magnifying endoscopy observations and studies of the molecular profile of early esophageal cancer, we conclude that two major angiogenic steps exist in precancerous and M3 lesions in the early phase of cancer progression. In addition, it is now possible to study cell morphology using an endocytoscope with a much higher magnification (×400-×1000) than magnifying endoscopes currently on the market. The histology revealed in this way may reduce the need for conventional biopsy histology in the future.