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.
Inclusion Criteria:
A. Age, between 20 and 80 B. Patients with undifferentiated gastric cancer who will be underwent surgery
Exclusion Criteria:
A. Previous subtotal gastrectomy B. Previous EMR/ESD history C. Significant cardiopulmonary disease D. Active hepatitis or severe hepatic dysfunction E. Severe renal dysfunction F. Severe bone marrow dysfunction G. Severe neurologic or psychotic disorder H. Pregnancy or breast feeding