Zheng X, et al. - Given the significance of assessing whether residual cancer cells exist in the endoscopic submucosal dissection [ESD; the primary option for the treatment of early gastric cancer (EGC)] specimen margins, researchers investigated multiphoton microscopy (MPM) for its utility in the diagnosis of ESD specimen margins in the case of EGC. Using the proposed MPM technique, they imaged a total of 20 surgical samples to obtain two-photo excited fluorescence signal from the intrinsic fluorescent substances within cells and second-harmonic generation signal from collagen; MPM pathological features for margin diagnosis were determined using these signals. Then, they conducted a double-blind study of 50 samples evaluating the diagnosis results based on the obtained MPM pathological features. They identified that the cytological and morphological differences between tissue in the negative and positive margin could be accurately identified using multiphoton microscopy. Findings suggest the potential utility of MPM as an effective, real-time, and label-free novel method to determine intraoperative resection margins.