Expression of E-cadherin, b-catenin, and Ki-67 in goblet cell carcinoids of the appendix: an immunohistochemical study with clinical correlation.

Goblet cell carcinoid (GCC) of the appendix is a rare entity, of which both the histogenesis and biologic behavior remain controversial, and prognostic tools and therapeutic strategies for this unusual tumor have yet to be defined. The aim of this study was to analyze expression of E-cadherin and b-catenin in GCCs of the appendix with long-term follow-up data as related to the expression of Ki-67 proliferation marker to provide a rationale for treatment guidelines. We analyzed the expression of E-cadherin, b-catenin, and Ki-67 in 11 GCCs of the appendix and control groups of typical carcinoids of the large intestine (n = 29), well to moderately differentiated adenocarcinomas of the colon (n = 10), poorly differentiated adenocarcinomas of the colon (n = 12), and normal appendiceal tissues (n = 10). There was no significant difference between the GCCs and normal appendiceal tissues regarding the expression of E-cadherin or b-catenin (p = 0.297 and 0.103, respectively). The percentage of positive GCC cells ranged between 0.52 and 10.35% (4.27 +/- 0.80), and only one case had a score >10%. Metastatic tumor spread and death were found in high MIB-1 labeling index (LI) cases of GCC (>3%). Our findings suggest that the behavior of the majority of GCCs might be indolent and different from adenocarcinomas because of the preserved expression of E-cadherin and b-catenin and relatively low MIB-1 LI. However, some of these tumors act aggressively and MIB-1 LI might be a good parameter to determine the therapeutic procedure.