Importance of proliferation markers in gastrointestinal carcinoid tumors: A clinicopathologic study

Background/Aims: Carcinoma tumors are common tumors in the gastrointestinal tract, certain criteria such as the depth of invasion, the localization, t he tumor size, the mitotic index and the pattern of ploidy are used to dete r-mine the potential biological behavior of these tumors some of which migh t be malignant. The goal, of this study was to assess the prognostic signif icance of proliferation markers (Ki67 and PCNA) in carcinoid tumors by usin g immunohistochemistry. Methodology: An immunostaining in 37 carcinoid tumors arising in various lo cations of the gastrointestinal tract was performed. The best stained area was selected and 1000 neoplastic cells were counted in order to determine t he proliferation index in each case. Results: The results of proliferation index were compared with the depth of invasion, the embryologic type, the tumor size, the presence of metastases and disease-free survival by using statistical methods. The Ki67 tumor pro liferation index in the tumors >2.1cm was significantly different from the tumors less than or equal to 2cm (P=0.032). Conclusions: The presence of significant correlation between Ki67 positivit y and the tumor size might suggest that Ki67 antibody can be useful for the determination of potential behavior of gastrointestinal carcinoid tumors.