MKI67 and lung carcinoid tumor: Costes et al. [12] in a study of 47 resected lung carcinoid tumors (31 TCs and 16 ACs) using a computer assisted image processor reported that, compared to typical carcinoids, atypical carcinoids have a higher expression of Ki-67 labeling expressed in percentage of stained nuclear surface relative to the total nuclear surface area (mean 0.45% versus 2.45%  P = 0.0035).