Role of Probe-based Confocal Laser Endomicroscopy Targeted Biopsy in the Molecular Study of Undifferentiated Gastric Cancer

The purpose of this study is to conduct a study on genetic pathology, obtaining of pure cancer tissues is mandatory. Although the endoscopy with biopsy has been a gold standard for diagnosing gastric cancer, percentage of cancer cells in biopsy samples is usually 30% or less. Recently, confocal laser endomicroscopy has been introduced for real-time histopathologic diagnosis in various cancers. In previous pilot study in our institution, pCLE-targeted biopsy provided superior results in terms of the proportion of cancer cells in biopsy samples compared to WLE-targeted biopsy, especially for gastric cancers with undifferentiated histology. However, there was a limitation because of small sample size. Therefore, the investigators aim to evaluate that biopsy using probe-based confocal laser endomicroscopy for undifferentiated gastric cancer will increase the percentage of cancer cells and expression ratio of tumor marker in biopsy samples.