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Objective: Tight junction proteins have recently been reported to be useful for distinguishing between neoplastic and non-neoplastic tissues. In this study, we evaluated the expression and localization of tight junction transmembrane proteins in human cervical adenocarcinoma and adenocarcinoma in situ (AIS), and we determined whether their expression patterns could distinguish cervical adenocarcinoma from non-neoplastic cervical glands., Methods: Fifty-five patients with cervical adenocarcinoma or AIS were included in this study. Surgical specimens were immunohistochemically stained for claudin (CLDN) -1, -4, -7, occludin, and JAM-A., Results: Significantly higher expression levels of CLDNs and JAM-A were found in cervical AIS and adenocarcinoma than in non-neoplastic glands. In cervical AIS and adenocarcinoma, localization of CLDN1 and JAM-A was extended throughout the whole cell membranes, whereas they were predominantly expressed at the most apical cell-cell junction in non-neoplastic glands. ROC curve analysis revealed that immunoreactivities of CLDN-1 or JAM-A successfully distinguished neoplasms from non-neoplastic cervical glands with high specificity (CLDN-1, 79.1%; JAM-A, 79.1%) and high sensitivity (CLDN-1, 84.1%; JAM-A, 95.5%)., Conclusions: As expected, there were immunohistochemical differences between cervical adenocarcinoma and non-neoplastic cervical glands by using antibodies against tight junction transmembrane proteins. These results suggest that CLDN-1 and JAM-A are potential biomarkers for cervical adenocarcinoma.

Background Lymphovascular invasion is an important pathway of metastatic spread and regional lymph node metastasis is the major prognostic factor in prostatic adenocarcinoma. D2-40 is used to identify the lymphatic vessels and to assess the lymphatic vessel density (LVD). Expression of claudin-4 may be related to invasion and progression of carcinoma cells in several primary tumors. Aim To evaluate intra- and peritumoral LVD through immunohistochemical expression of D2-40 in relation to claudin-4 expression and clinicopathological parameters in prostatic adenocarcinoma. Materials and Methods Immunohistochemical staining procedure was performed on 53 paraffin-embedded blocks of radical prostatectomy specimens for prostatic adenocarcinoma using anti D2-40 and claudin-4 antibodies. Sections were evaluated for mean LVD in intratumoral and peritumoral tissues assessed by D2-40 expression. Results LVD in intratumoral tissues was significantly lower compared with peritumoral areas (P = .0001). Peritumoral mean LVD was significantly higher in cases with lymphovascular invasion (P = .041) and in cases with positive lymph node metastasis (P = .003) than intratumoral mean LVD. High claudin-4 expression was significantly correlated with high tumor grade (P = .0001), lymphovascular invasion (P = .006), and positive lymph node metastasis (P = .004). High claudin-4 expression was significantly associated with increased mean LVD in peritumoral tissues. Conclusion Increased peritumoral mean LVD in prostatic adenocarcinoma is associated with lymphovascular invasion and positive lymph node metastasis. High claudin-4 expression is associated with high tumor grade, lymphocascular invasion, positive lymph node metastasis, and high mean peritumoral LVD suggesting that D2-40 and claudin-4 may represent different mechanisms of lymphatic vessel invasion with both biomarkers is related to poor prognosis., (© The Author(s) 2015.)

Recently, there is growing evidence that tight junction proteins are often abnormally regulated in human tumors. The function of tight junction proteins in the maintenance of normal epithelial physiology has been well discussed, but their role in the tumorigenesis of gastric cancer is less well defined. To explore the expression distinction of the tight junction proteins claudin-1, -3, and -4 expression in the gastric cancer, the expression of claudin-1, -3, and -4 in 92 gastric cancer tissues and the non-neoplastic tissues adjacent to the tumors were examined by immunohistochemistry. Compared with adjacent non-neoplastic tissues, the expression of claudin-1 was down regulated. However, the expression of claudin-3 and claudin-4 were up-regulated in gastric cancer tissue. In addition, the expression of claudin-3 is correlated with claudin-4 expression in gastric cancer. Our present study reveals that claudin-1, -3, and -4 protein expression altered between human gastric cancers and adjacent non-neoplastic tissues.

Background: Adenocarcinoma can be challenging to distinguish from malignant mesothelioma in effusions, and this distinction often requires ancillary studies and clinical correlation. Immunohistochemistry for claudin-4, a tight-junction-associated protein, has recently been shown to distinguish adenocarcinoma from malignant mesothelioma, mostly in surgical specimens. Our aim was to validate and assess the immunoreactivity profile of claudin-4 in a large series of malignant effusions., Methods: We evaluated 159 malignant effusions (84 adenocarcinomas and 75 malignant mesotheliomas). Claudin-4 immunohistochemistry was performed on cell-block paraffin sections and scored for staining intensity, staining pattern (cytoplasmic versus membranous), and percentage of positive tumor cells. Appropriate positive and negative controls were used throughout., Results: All cases of mesothelioma were negative for claudin-4 (0 of 64). Eighty-three of 84 cases of adenocarcinoma were positive (99%); 1 case of serous carcinoma was negative. Most adenocarcinomas showed strong and diffuse membranous staining (71 of 84; 84%); 12 cases (14%) showed membranous staining of moderate intensity. The overall sensitivity for adenocarcinoma was 99% (83 of 84)., Conclusions: Claudin-4 immunohistochemistry effectively distinguishes adenocarcinoma from malignant mesothelioma with high sensitivity and specificity in the evaluation of malignant effusions., (© 2014 American Cancer Society.)