RT Journal Article SR Electronic T1 Low Expression of Claudin-1 and Presence of Poorly-differentiated Tumor Clusters Correlate with Poor Prognosis in Colorectal Cancer JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 3301 OP 3306 VO 33 IS 8 A1 MASATSUNE SHIBUTANI A1 EIJI NODA A1 KIYOSHI MAEDA A1 HISASHI NAGAHARA A1 HIROSHI OHTANI A1 KOSEI HIRAKAWA YR 2013 UL http://ar.iiarjournals.org/content/33/8/3301.abstract AB Background: Claudins are integral membrane proteins that constitute tight junctions. The aim of this study was to determine the clinical significance of claudin-1 in terms of the cell–cell adhesion, considering the poorly-differentiated tumor component. Patients and Methods: A total of 344 cases of stage II and III colorectal cancer were enrolled. We evaluated the expression of claudin-1 by immunohistochemistry and the extent of the poorly differentiated component. Results: Low expression of claudin-1 was associated with lymphatic involvement, histological differentiation, extent of poorly-differentiated component, reduced disease-free and overall survival. Multivariate analysis indicated that lymph node metastasis, venous involvement and low claudin-1 expression were independent predictors of recurrence, and that lymph node metastasis, venous involvement and low claudin-1 expression were associated with poor survival. Conclusion: Our study not only showed the significance of low expression of claudin-1 as a predictor of poor prognosis of colorectal cancer but also supported the concept of grading of the poorly-differentiated component.