Loss of Chromosome 13q is Associated with Malignant Potential in Pulmonary Carcinoids

Abstract

Background: Genetic differences between pulmonary typical carcinoids (TCs) and atypical carcinoids (ATCs) still remain controversial and no genetic marker is available for the evaluation of the malignant potential in pulmonary carcinoids. Materials and Methods: Five TCs and 3 ATCs were analyzed concurrently by comparative genomic hybridization (CGH) and cytogenetics to investigate the chromosomal abnormalities with reference to malignant potential. As parameters for biological aggressiveness, mitotic counts, necrosis, lymph and blood vessel invasion, lymph node and organ metastasis and Ki-67 index were used. Results: Using CGH analysis, chromosome 13q loss was observed in 4 cases, of which 3 were ATC cases and 1 was a TC case with aggressive features. All the cases without 13q loss showed no aggressive features. Upon immunohistochemical analysis, RB protein expression was detected regardless of the 13q status. Conclusion: The results of this study indicate that another tumor suppressor gene on 13q may be involved in the malignant potential in pulmonary carcinoids.