None of these risk factors were contraindications to laparoscopic cholecystectomy. This may help predict the difficulty of the procedure and permit the surgeon to better inform patients about the risk of conversion from laparoscopic to open cholecystectomy.

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Epithelial (E)-cadherin and its associated cytoplasmic proteins (␣-, ␤-, and ␥-catenins) are important mediators of epithelial cell-cell adhesion and intracellular signaling. Much evidence exists suggesting a tumor͞invasion suppressor role for E-cadherin, and loss of expression, as well as mutations, has been described in a number of epithelial cancers. To investigate whether E-cadherin gene (CDH1) mutations occur in colorectal cancer, we screened 49 human colon carcinoma cell lines from 43 patients by single-strand conformation polymorphism (SSCP) analysis and direct sequencing. In addition to silent changes, polymorphisms, and intronic variants in a number of the cell lines, we detected frameshift single-base deletions in repeat regions of exon 3 (codons 120 and 126) causing premature truncations at codon 216 in four replication-errorpositive (RER؉) cell lines (LS174T, HCT116, GP2d, and GP5d) derived from 3 patients. In LS174T such a mutation inevitably contributes to its lack of E-cadherin protein expression and function. Transfection of full-length E-cadherin cDNA into LS174T cells enhanced intercellular adhesion, induced differentiation, retarded proliferation, inhibited tumorigenicity, and restored responsiveness to the migratory effects induced by the motogenic trefoil factor 2 (human spasmolytic polypeptide). These results indicate that, although inactivating E-cadherin mutations occur relatively infrequently in colorectal cancer cell lines overall (3͞43 ‫؍‬ 7%), they are more common in cells with an RER؉ phenotype (3͞10 ‫؍‬ 30%) and may contribute to the dysfunction of the E-cadherin-catenin-mediated adhesion͞sig-naling system commonly seen in these tumors. These results also indicate that normal E-cadherin-mediated cell adhesion can restore the ability of colonic tumor cells to respond to trefoil factor 2.

E‐cadherin is a calcium‐dependent cell–cell adhesion molecule expressed by melanocytes and responsible for their adhesion to keratinocytes in vitro. In this study, the expression of E‐cadherin and its associated cytoplasmic proteins α‐, β‐, and γ‐catenin was evaluated in melanocytic lesions by immunohistochemistry. E‐cadherin expression was evaluated in 70 malignant melanomas and the catenins in 35 of these specimens. Twenty benign melanocytic naevi were also evaluated for E‐cadherin and catenin expression. In normal epidermis, E‐cadherin/catenin immunostaining was localized at the intercellular borders. In melanomas, a differential loss of E‐cadherin expression was observed. Membranous E‐cadherin staining was absent in dermal nests of melanomas in their radial growth phase and in Clark level II and III lesions, whereas it was present in a high proportion of melanomas in their vertical growth phase, in Clark level IV and V lesions and in metastasizing melanomas. In contrast, superficial compartments of naevi showed membranous E‐cadherin immunoreactivity and junctional naevus cell nests displayed heterogeneous or diffuse cytoplasmic staining. Cytoplasmic α‐ and β‐catenin, but not γ‐catenin staining were detected in all benign and malignant lesions. These findings indicate that qualitative changes in the expression and cellular localization of E‐cadherin and of α‐, β‐, and γ‐catenin occur in melanocytic lesions and may reflect different stages in their progression. Copyright © 1998 John Wiley & Sons, Ltd.

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