The molecular mechanism underlying cancer invasiveness and metastasis of gastric carcinoma remains elusive. Here, we reported significant decrease in microRNA (miRNA)-34a and significant increase in phosphorylated epidermal growth factor receptor (EGFR) and matrix metalloproteinase-7 (MMP7) in the resected gastric carcinoma from the patients, compared with adjacent normal tissue. Moreover, strong correlation was detected among these three factors. To examine whether a causal link exists, we used two human gastric carcinoma lines, SNU-5 and HGC27, to study the molecular basis of miRNA-34a, EGFR signaling, and MMP7 activation. We found that EGF-induced EGFR phosphorylation in SNU-5 or HGC27 cells activated MMP7 and consequently cancer invasiveness. Both an inhibitor for EGFR and an inhibitor for Akt significantly inhibited the EGF-induced activation of MMP7, suggesting a phosphatidylinositol 3-kinase (PI3K) signaling cascade dependent pathway. Moreover, miRNA-34a levels were not affected by EGF-induced EGFR phosphorylation. However, overexpression of miRNA-34a antagonized EGF-induced MMP7 activation without affecting EGFR phosphorylation in SNU-5 or HGC27 cells. Taken together, our data suggest that miRNA-34 inhibits EGFR signaling via downstream PI3K signaling cascades to regulate MMP7 expression in gastric carcinoma. Thus, miRNA-34a, EGFR, and MMP7 appear to be promising therapeutic targets for preventing the metastasis of gastric carcinoma.

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BackgroundTelepathology (TP) provides remote pathology services for primary diagnosis practices, including intraoperative consultation of surgical pathology; it has not been widely implemented in China. In this study, the results of an implementation were reported, which lasted for two and a half years, and demonstrated the experience of the diagnosis of the intraoperative frozen sections by using TP consultation platform of Southern Medical University and Guangzhou Huayin Medical Laboratory Center (SMU-HUAYIN TP) in China.MethodsThe SMU-HUAYIN TP consultation platform connects 71 participating basic hospitals and 11 senior pathologists. Nanfang Hospital is a high-level hospital located in a large city in China. This retrospective study summarizes the experience and results of TP for frozen section diagnosis by comparing the data of the platform and Nanfang Hospital over a period of 2.5 years from January 2015 to June 2017.ResultsA total of 5233 cases were submitted to the platform, including 1019 cases in 2015, 2320 cases in 2016, and 1894 cases in 2017. The most common cases were breast (30.42%), followed by thyroid (29.05%) and gynecological (24.86%). Average turn-around time (TAT) of the cases from the platform in 2015 and 2016 was controlled within 30 min. In most TP cases (90.31%) and cases from Nanfang Hospital (86.14%), a definitive diagnosis was provided. The coincidence rate was 99.77% in the TP cases and 99.35% in the cases from Nanfang Hospital. The false positive and false negative rates of TP cases were 0.04 and 0.19%, respectively and no significant difference was found among different senior pathologists (P = 0.974, P = 0.989, P > 0.05). Similarly, there was no significant difference between TP cases and cases from Nanfang Hospital that were diagnosed by the same senior pathologist (P > 0.05).ConclusionsOur results indicate that TP in frozen section diagnosis could improve patient care and solve the problem of unevenly distributed pathology resources in China. We believe that in the near future, TP in frozen section diagnosis will become an important component of telemedicine and will play a significant role in health care reform in China.

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The efficiency and safety of charcoal nanoparticle tattooing in localizing unpalpable colonic small lesions for later laparoscopy is described. Twenty six patients were enrolled for this prospective study. Tumor sites were localized with charcoal nanoparticles during colonoscopy for later laparoscopic colorectal operations. In all patients, the entire colon was examined preoperatively by colonoscopy and 0.5 ml (5 mg) of charcoal nanoparticle was injected submucosally near lesions or polypectomy sites. During laparoscopic colorectal operations for these biopsy-proven tumors, tumors were easily identified. The mean resection margin was 3.13 +/- 2.01 cm. The mean length of resected intestinal segment was 12.69 +/- 4.39 cm. No tumor was found at the resection line as indicated by postoperative pathological examination. Most importantly, no wrong segment was resected. Thus we show that easy identification of tumor can be achieved by preoperative tattooing with charcoal nanoparticles. Further studies regarding the long-term tattooing of tumor with charcoal nanoparticles are warranted.