A novel endoscopic device for retrieval of polyps resected from the colon and rectum.

BACKGROUND: Retrieval of polyps resected from the colorectum is time consuming, despite the availability of various devices, such as grasping forceps, nets, and suction traps, for this purpose. A novel device for retrieval of polyps was developed and tested. METHODS: Patients with polyp(s) less than or equal to 6 mm in diameter were included in this study. The effectiveness of the device for polyp retrieval was evaluated. OBSERVATIONS: In total, 180 of 184 polyps were retrieved from 100 patients. Four polyp specimens (2.2%) were lost after polypectomy. None of the retrieved specimens were damaged. All retrieved polyps could be assessed histopathologically, and a definitive diagnosis was made. CONCLUSIONS: The newly developed device proved to be reliable when used in clinical practice.

Redifferentiation and ZO-1 reexpression in liver-metastasized colorectal cancer: possible association with epidermal growth factor receptor-induced tyrosine phosphorylation of ZO-1.

Tubular gland structures of colorectal cancer (CRC) have been demonstrated to undergo dedifferentiation at the primary site, and then the gland structures are re-formed in the liver metastases. In this study, we examined the degree of differentiation of the gland structure of 48 cases of CRCs (24 cases with synchronous liver metastasis, 24 cases without metastasis) by the modified Gleason grading system. We also investigated the role of ZO-1, one of the tight junction proteins, in the morphological changes, i.e., dedifferentiation and redifferentiation, of CRCs at the primary site and liver metastases. Liver-metastasized CRCs (2.47+/-0.37) showed a lower score in the modified Gleason grading system than the corresponding primary tumors (3.28+/-0.36) did, i.e., the tumor cells had undergone redifferentiation at liver metastases. ZO-1 was expressed at the apical cell borders of normal colorectal epithelium, the luminal side of which has tubular gland structures. In comparison with this normal epithelium, the ZO-1 expression level was frequently reduced in primary CRC with liver metastasis (20.8%) and ZO-1 was reexpressed in liver metastasized cancers (79.2%). Furthermore, it was demonstrated by an immunoprecipitation-western blotting analysis on 5 cases of CRC with liver metastasis that ZO-1 bound to epidermal growth factor receptor (EGFR) irrespective of the phosphorylation status of EGFR, and that EGFR associated ZO-1 was highly tyrosine-phosphorylated only in the primary CRC, but was dephosphorylated in the liver-metastasized cancers. Our observations suggest that tyrosine phosphorylation of ZO-1 leads to down-regulation of the function of ZO-1 and dedifferentiation of the glands in CRCs, and these phenomena contribute to liver metastases, and redifferentiation of the glands occurs in the liver metastases.