Proposed genomic progression model for ileal carcinoids. Two distinct groups of sporadic ileal carcinoids can be identified: a larger group of tumors (65–75%) which is characterised by loss of chromosome 18. Loss of chromosome 18 is an early and pathogenetic event in these tumors. During tumor progression, additional aberrations accumulate, in particular losses on chromosomes 3p, 11q, and 13. A smaller group of tumors (25–35%) is characterised by clustered gains on chromosomes 4, 5, 7, 14, and 20. These tumors frequently have an intact chromosome 18. Gain of chromosome 7 is associated with metastases and solid growth pattern, while gain of chromosome 14 has been associated with shorter patient survival. The model is based on data from references [69–71].
