An innovative technique for endoscopic submucosal dissection of early gastric cancer using a new spring device.

BACKGROUND AND STUDY AIMS: In recent years, endoscopic submucosal dissection (ESD) has been applied for the treatment of gastric tumors, and the en-bloc resection rate of early gastric cancer has greatly improved. Herein, we introduce spring-assisted ESD, for quicker submucosal dissection. PATIENTS AND METHODS: ESD was carried out in 32 patients (20 men, 12 women; mean age 72.6 years, range 53 - 88 years) for early gastric cancer, with tumors over 10 mm in diameter. The patients were divided retrospectively into two groups (spring-assisted ESD, n = 20; conventional ESD, n = 12). To comparatively evaluate the performance speed of ESD, the circumferential length and the area of the resected specimen were calculated by the approximation formula for ellipse. Then, the circumferential cutting speed, the submucosal dissection speed, and the total ESD speed were calculated as index scores. The scores for spring-assisted ESD and conventional ESD were compared. RESULTS: The mean (+/-SD) circumferential cutting speeds in spring-assisted ESD and conventional ESD were 0.53 +/- 0.27 and 0.60 +/- 0.30 cm/minute, respectively ( P = 0.51). The mean submucosal dissection speeds in spring-assisted ESD and conventional ESD were 0.67 +/- 0.41 and 0.32 +/- 0.24 cm (2)/minute, respectively ( P = 0.005). The mean total ESD speeds in spring-assisted ESD and conventional ESD were 0.25 +/- 0.10 and 0.17 +/- 0.07 cm (2)/minute, respectively ( P = 0.015). The mean total ESD times were 57 and 75 minutes in the spring and conventional group, respectively ( P = 0.30). CONCLUSION: Using the aforementioned indices, we evaluated the performance speed of ESD. Spring-assisted ESD may allow faster submucosal dissection.

Instability of X chromosome methylation in aberrant crypt foci of the human colon.

Aberrant crypt foci (ACF) in the colon have long been thought to be precancerous lesions and therefore monoclonal, but this is unresolved. Eleven ACF were isolated from five female patients. From these ACF, 178 individual aberrant crypts (ACs) were obtained and assessed for clonality using a method based on X chromosome inactivation of the polymorphic X-linked human androgen receptor (HUMARA) gene. Ten ACF were found to be mixtures of monoclonal and polyclonal types. The HUMARA analysis indicated that almost all ACF were polyclonal lesions. Simultaneously, we investigated K-ras mutations in each AC. We found that seven of the ACF harbored the K-ras mutation; strikingly, this was concordant for all of the ACs from a single ACF. These results, by contrast to the results of HUMARA analysis indicate that ACF lesions are monoclonal. This discrepancy suggests that ACF are apparently polyclonal because of de novo methylation on the active X chromosome. To confirm this possibility, we investigated the methylation status of the X chromosome in male ACF using a competitive PCR assay. One hundred nineteen individual ACs were isolated from eight ACF derived from four male patients. A total of 47 of 119 (39%) of male ACs showed de novo methylation of the HUMARA gene. We found that six of the eight male ACF harbored the K-ras mutation, and this was concordant for all of the ACs from a single ACF. We conclude that X chromosome methylation is unstable in ACF and that this might be an early event in colon carcinogenesis.