E-cadherin as tumor differentiation marker and as architectural determinant

Role of Receptor Profiling for Personalized Therapy in a Patient with a Growth Hormone-Secreting Macroadenoma Resistant to First-Generation Somatostatin Analogues

Background: Acromegaly is almost always caused by a pituitary adenoma and is associated with high morbidity and mortality when uncontrolled. Trans-sphenoidal removal of the adenoma is the mainstay of therapy, but fails to control the disease in a significant number of patients who require further treatment. Somatostatin analogues (SSAs) as monotherapy or in combination with growth hormone (GH)-receptor antagonists and/or dopamine agonists are used either alone or in combination following surgical failure to achieve disease control. The use of specific biomarkers may help to individualize the therapeutic plan after surgical failure and direct towards a more personalized approach. Methods: We report a 41-year-old man with acromegaly and residual disease after repeated surgery that was resistant to first-generation SSAs. Results: Biochemical and tumor control were achieved following the administration of a second-generation SSA, pasireotide, combined with pegvisomant, both at maximal doses and along with cabergoline. Histology specimens showed a sparsely-granulated GH-immunostaining pituitary adenoma with intense positivity for somatostatin receptors 2 and 5 and low levels of E-cadherin. Conclusion: Personalized medical therapy guided by currently available biomarkers, such as immunohistochemically-characterized receptor profiling or adhesion molecules, resulted in controlled insulin-like growth factor-1 (IGF-1) and GH levels and symptom alleviation following the combination of three drug-classes.

Nup88 (karyoporin) in human malignant neoplasms and dysplasias: correlations of immunostaining of tissue sections, cytologic smears, and immunoblot analysis

Nuclear pore complexes (NPCs) are elaborate macromolecular structures that regulate the bidirectional nucleocytoplasmic traffic system. In vertebrate cells, NPCs include a family of 50 to 100 proteins termed nucleoporins (Nups). The 88-kD Nup has been found to be linked in a dynamic subcomplex with the oncogenic CAN/Nup214. Applying a polyclonal antiserum to Nup88 on paraffin sections, we found that it immunoreacts with numerous malignant neoplasms. All carcinomas reacted irrespective of site, type, or degree of differentiation; often, high-grade carcinomas stained more strongly and extensively. Some sarcomas (e.g., fibrosarcomas, leiomyosarcomas, liposarcomas, and rhabdomyosarcomas) reacted intensely; melanomas, gliomas, mesotheliomas, and malignant lymphomas also stained. In situ carcinomas of the colon, stomach, breast, and prostate stained convincingly, as did in situ melanomas; some samples of fetal tissues also reacted. Cytologic smears of some of the aforementioned tumors also stained. In selected samples, enhanced immunostaining of tissue sections and cytologic smears correlated strongly and consistently with immunoblot data. Immunoblots of the same tumors with antibodies to 2 other Nups (Nup214 and Nup153) showed no comparable enhancement. Therefore, it seems that in some malignant tumors, Nup88 overexpression is not parallelled by an overexpression of other Nups. Benign tumors, hyperplasias, and normal tissues showed weak and sporadic staining or absence of staining; immunoblots of the same samples yielded weak signals. Occasional highly proliferative hyperplastic-reactive processes showed focal staining. Thus, our correlative histologic, cytologic, and molecular data indicate that Nup88 may be viewed as a potentially useful, broadly based histodiagnostic and molecular marker of many malignancies and premalignant dysplasias, and further suggest that in some malignant tumors, Nup88 may be selectively overexpressed as compared with other Nups. Thus, we propose that Nup88 be designated as karyoporin.

Ki67, E-cadherin, and p53 as prognostic indicators of long-term outcome after liver transplantation for metastatic neuroendocrine tumors

BACKGROUND

Patients suffering from hepatic metastases of neuroendocrine tumors (NET) are potential candidates for orthotopic liver transplantation. Because recurrence rates are high and outcome is variable, prognostic indicators are required. The aim of our study was to identify predictors of long-term survival with a focus on the impact of tumor biology.

METHODS

We retrospectively analyzed 19 patients who received an orthotopic liver graft for metastatic NET at the Medizinische Hochschule Hannover. Expression of Ki67, E-cadherin, and p53 was studied immunohistochemically in metastases of neuroendocrine tumors of the explanted livers.

RESULTS

Patients were followed up to 146 months after liver transplantation. Six patients died during follow-up. The resulting 1-, 5-, and 10-year survival rates are 89%, 80%, and 50%, respectively. All deaths during long-term follow-up were tumor-associated. Recurrence was diagnosed in 12 patients between 2 weeks and 48 months after liver transplantation. Three patients are without tumor recurrence more than 8 years after liver transplantation. Survival in the 5 patients with low Ki67 and regular E-cadherin staining was significantly better than in the 12 patients with high Ki67 or aberrant E-cadherin expression (7-year survival 100% vs. 0%, respectively, log rank P=0.007). p53 expression did not significantly improve prognostic accuracy.

CONCLUSIONS

We conclude that analysis of Ki67 and E-cadherin expression may improve the identification of patients with a favorable prognosis after liver transplantation for metastatic neuroendocrine tumors.

Expression of E-cadherin and p53 proteins in human soft tissue sarcomas

OBJECTIVE

To investigate the expression of E-cadherin in human soft tissue sarcomas and its potential relationship to p53 alterations.

DESIGN

Tissue sections of 91 soft tissue sarcomas were analyzed by immunohistochemistry for E-cadherin and p53 proteins. Sixty-one tumors were investigated further by the application of the polymerase chain reaction technique and a direct sequence analysis procedure of exons 5 through 8 in the p53 gene.

SETTING

Tertiary-care teaching hospital.

PATIENTS

Ninety-one patients with soft tissue tumor were treated surgically. Thirteen of these patients had tumors with epithelial differentiation.

RESULTS

E-Cadherin was expressed at the cell-cell boundaries in 11 samples (12%): 9/13 (69%) with and 2/78 (3%) without histologic evidence of epithelial elements. Other sarcomas were completely negative for E-cadherin. Overexpression of p53 was detected in 30 cases (33%), 7 of which also demonstrated mutations in the p53 gene. The frequencies of p53 abnormalities in tumors with and without epithelial components were 8% and 37%, respectively. No association was established between E-cadherin immunoreactivity and p53 abnormalities (P =.13). Tumor grade strongly correlated with p53 alterations (P =.01), but not with E-cadherin expression (P =.07).

CONCLUSIONS

These data support the involvement of p53 alterations in the pathogenesis of soft tissue sarcomas. The lack of E-cadherin expression in these tumors, with the exception of lesions showing epithelial differentiation, indicates that E-cadherin is not an important factor involved in cell-cell adhesion in sarcomas. It is, however, suggested that E-cadherin may play a role in the development and/or maintenance of epithelial architecture in sarcomas, regardless of p53 status.

A novel, nuclear pore-associated, widely distributed molecule overexpressed in oncogenesis and development

Nuclear pore complexes are large, elaborate macromolecular structures that mediate the bidirectional nucleocytoplasmic traffic. In vertebrates, nuclear pore complexes comprise 50 to 100 proteins termed nucleoporins (Nup). An 88-kd nucleoporin (Nup88) has been recently cloned and characterized, and found to be associated in a dynamic subcomplex with the oncogenic nucleoporin CAN/Nup 214. We have produced a polyclonal antiserum to Nup88, and found that it immunoreacts convincingly in conventional tissue sections of 214 samples of malignant tumors of many types. All carcinomas were stained irrespective of site or line of differentiation; the majority of cases reacted strongly and extensively. In situ carcinomas and highly dysplastic epithelia were similarly reactive. Samples of malignant mesotheliomas, gliomas, sarcomas, and lymphoreticular tumors were also stained. Substantial reactions were also found in certain fetal tissues. Focal reactions were noted in some reactive-proliferative processes. Most benign epithelial and mesenchymal tumors and hyperplasias, and normal adult tissues reacted weakly and sporadically or not at all. Immunoblot analysis of selected samples strongly corroborated those findings. If further substantiated, our findings indicate that Nup88 could be regarded as a selective yet broadly based proliferation marker of potential significance in the histological evaluation and diagnosis of malignant transformation. Its ready applicability on conventional paraffin sections and on cytological preparations may broaden its clinical and investigative significance.