Background: During tumorigenesis of gastrointestinal stromal tumors (GISTs), the most frequent changes are reported to be gain-of-function mutations in the C-KIT proto-oncogene. However, we speculated that additional genetic alterations are required for the progression of GISTs.
Patients and methods: Using 15 cases diagnosed with GISTs, we searched for novel indicator genes by microarray analyses using an Oligo GEArray(R) PI3K-AKT Signaling Pathway Microarray Kit. In addition, we analyzed the mutational status of C-KIT and the proliferation status indicated by the Ki-67 index.
Results: The tumor localizations of the 15 GISTs were as follows: 8 in the stomach; 2 in the small intestine; 2 in the mesentery; 1 in the duodenum; 1 in the rectum; and 1 in liver. Regarding the C-KIT gene analysis, mutations in exon 11 were detected in 11 out of 13 patients. In 1 out of the 13 patients, mutations were detected in both exons 11 and 13. No genetic abnormalities were identified in 1 patient. The Ki-67 labeling indices were significantly lower for the low-risk and intermediate-risk groups than for the high-risk group (p=0.0440). No specific genes were overexpressed in the >1% Ki-67 group. Regarding the primary lesion sites, the following 6 genes were overexpressed in tumors in the stomach: RBL2, RHOA, SHC1, HSP90AB1, ACTB and BAS2C.
Conclusion: Gene analysis is currently only useful for diagnostic assessment and predicting therapeutic effects. However, it may be possible for new malignancy-related factors to be identified by comparing and investigating gene expression levels and other factors using such analyses.