OBJECTIVETo construct tree models for nasopharyngeal carcinoma (NPC)and explore the oncogenesis process of NPC.

METHODSBased on the software which Desper et al developed, tree models were constructed for colorectal carcinoma (CC) from the comparative genomic hybridization (CGH) data of 118 CC patients and for NPC from the CGH data of 140 southern Chinese patients, respectively.

RESULTSTree models for CC suggested that changes in -18q and +20q were important early events in colorectal carcinogenesis. As changes in -18q occurred prior to those in -17p, there might be some cause-effect relationship. Tree models for NPC suggested that change in -3p was an important early event in nasopharyngeal carcinogenesis, and those in -11q, -14q, -16q, -9p were also non-random genetic events in carcinogenesis, suggesting that there might be tumor-associated genes existing on these chromosome arms. The tree model also suggested the existence of oncogene on the short arm of chromosome 12.

CONCLUSIONConstructing tree models based on the CGH data to demonstrate the initiation and progression of NPC might help elucidate its multigene, multistep and multipathway development. It may provide valuable clues to explore the mechanism of tumorigenesis.