P30. Ki-67 expression in lung carcinoid tumors
Bernard Budimir1, Suzana Kukulj1, Luka Brcic2, Luka Opasic2, Branka Cucevic1, Marina Serdarevic1, Gordana Drpa1, Slavica Sovic3
Background: Ki-67 is nuclear protein with essential role in the control and timing of cell proliferation, largely studied in neuroendocrine tumors, but yet without clear clinical implications. A difference of percentage of Ki-67 labeling index (LI) was observed in different neuroendocrine tumors. This study intended to determine difference of Ki-67 LI between typical (TC) and atypical lung carcinoid (AC) using imunohistochemical methods, and to correlate clinical parameters with percentage of Ki-67 LI in TC and AC.
Methods and participants: A total of 49 specimens of TC and AC between year 2007 and 2009 were retrieved from our archive. Minimum follow-up period was 5 years. The clinical parameters included age, gender, tumor size, node and metastasis stage, recurrence of disease, therapy and overall survival (OS). Ki-67 was evaluated in the areas of highest positivity, and expressed as percentage of 400 tumor cells.
Results: Median value Ki-67 LI for atypical carcinoid was 17.1 (min 1.5, max 61.5). Median value Ki-67 LI for typical carcinoid was 3.8 (min 0.3, max 16). Although there is statistical difference in an average tumor size between AC and TC (P=0.02), there was no correlation between tumor size and Ki-67 expression. There was statistical difference between AC and TC concerning recurrence/metastatic disease (P=0.01) and OS (P=0.004), but none is in any relation with Ki-67 LI. The 5-year OS for typical carcinoid is 97.4% (95% CI: 97.3-97.5). The 5-year OS for atypical carcinoid is 60% (95% CI: 30-90).
Conclusions: Our study showed that Ki-67 LI was useful in dividing TC and AC, which is in concordance with published data. We also demonstrated that lower Ki-67 LI correlated with survival of the patients, regardless of carcinoid type. This study did not show any significant difference between AC and TC and Ki-67 LI in regards with age, gender, tumor size, recurrence/metastatic disease, therapy and overall survival, probably because small number of participants.
Keywords: Carcinoid; Ki-67
doi: 10.3978/j.issn.2218-6751.2014.AB042