Abstract
Aim: To evaluate the immunohistochemical expression of the markers Chromogranin A, Ki-67, CD99, EGFR in resected pulmonary neuroendocrine tumors (pNET).
Methods: Surgically resected specimen from 49 patients (men-31, 63.3%, women–18, 36.7%) with pNETs were studied: typical carcinod (TC)-20 (40.8%), atypical carcinoid (AC)-7 (14.3%), small cell lung carcinoma (SCLC)-20 (40.8%), and large cell neuroendocrine carcinoma (LCNEC)-2 (4.1%). The histological type, pTNM stage and the immunohistochemical expression of Chromogranin A, Ki-67, CD99 and EGFR was evaluated.
Results: The distribution in stages was as follows: TC & AC-I stage-20 (74.1%), II-5 (18.5%), IIIA-2 (7.4%); SCLC-IB-3 (15%), II-4 (20%), IIIA-9 (45%), IIIB & IV-4 (20%); LCNEC were in II stage. Neuroendocrine differentiation proved in all tumors by Chromogranin A. The mean values of Ki-67 were: TC-1.7%, AC–11.7%, SCLC–75.8%, LCNEC–63.5% (p=0.001). CD99 expression was proved in 22 (44.9%) of the cases (in 9 – it was expressed in 100% of the tumor cells). 11 (50%) of them were carcinoid tumors, 9 (40%) – SCLC, 2– LCNEC. 40% of all TC&AC express CD99. 45% of SCLC express CD99. In AC CD99 positive cases, Ki-67 was 22.3%, and in AC CD99 negative cases Ki-67 was 3.75% (p=0.008). From 49 cases in 10 (19.7%) an EGFR expression was observed – TC&AC-4 (20.4% of all carcinoids), SCLC-5 (25% of all SCLC), and LCNEC-1. In 3 of the carcinoid tumors and in 4 of the SCLC 100% of the tumor cells express the marker while in the remaining tumors it was clonal.
Conclusion: The CD99 expression correlates statisticaly significant with high Ki-67 index in AC. EGFR expressing NETs may be candidates for treatment with tyrosine – kinase inhibitors.
- © 2011 ERS