Expression Of FAK And C-myc Protein And Abnormality Chromosome 8 Numbers In Gastrointestinal Stromal Tumors And Their Significance

Objective:Gastrointestinal stromal tumors(GIST) is one of the most common mesenchymal tumors of the gastrointestinal tract. GISTs are believed to arise from pacemaker cell of intestinal tract—Cajal cell or lobus intermedius stem cells allied from Cajal cell. The histology morphous were spindle cell type, epithelioid cell type and the mixed type, and the positive expression of CD117 and DOG1 with immunohistochemistry. GIST has uncertain malignant potentiality, so it's biological behaviour was very difficult to predict. Therefore the biological behavior of GIST is currently a hot research. In this study we will investigate the correlation between heteroploid of chromosome 8 and FAK and C-myc protein expression in gastrointestinal stromal tumors and to predict the biological behavior about GIST.Methods:39 cases of samples were collected from 2008-2009 after operation, all GIST to confirm by histology and immunohistochemistry and then utilizing Fluorescence in situ hybridization (FISH) technique to study the abnormal occurrence of GIST of paraffin imbedding biopsy tissues; and to select the gene which Chromosome 8 may carry about FAK and C-myc, then using the immunohistochemistry to detect the expression of FAK and C-myc protein and to analyze the correlation with risk-grading by National Institutes of Health. Statistical analysis was performed using the SPSS 11.5 software.Results:(1) The chromosome 8 heteroploid was 21 cases about 39 cases of GIST, of which the polyploid was 17 and haploid was 4,there were significant difference between abnormality of chromosome 8 numbers and recurrence and metastasis, respectively (P<0.05), but was no related with the year, sex of patients and position and cell type of tumor (P> 0.05). Abnormality of chromosome 8 numbers in high risk-grading (Median/High risk) was more frequent than low risk-grading(Very low/Low risk) (P<0.05).(2) The positive rate of FAK expression was 48.7%(19/39), and were significant difference between recurrence and metastasis, respectively (P<0.05), was no related with the year, sex, position and cell type of tumor (P>0.05).FAK expression in high risk-grading was much more than low risk-grading (P<0.05).(3) The positive expression rate of Cmyc protein was 59.0%(23/39), and it was related with the metastasis (P<0.05),but no significant difference with the year, sex, position and cell type and recurrence of tumor (P>0.05). Cmyc expression was significant difference between very low risk GIST and median, high, and low risk GIST and high (P<0.05). Cmyc expression in high risk-grading was much more than low risk-grading (P<0.05).(4) The 12 cases occur both the polyploid of chromosome 8 numbers and positive expression of FAK protein, and there was significantly correlation between them from Spearman correlation analysis (r=0.385,.P=0.016).Similarly,there was 14 cases equation between the polyploid of chromosome 8 numbers and positive expression of C-myc protein, and showed a significant correlation between the two from statistical analysis (r=0.418,P=0.008).Conclusion:There was abnormality of chromosome 8 numbers which the polyploidy was more than monoploid of GIST, and gains of chromosomal 8 was frequent. The polyploidy of chromosome 8 numbers may carry the target gene about FAK and C-myc. The abnormality of chromosome 8 numbers and FAK and C-myc protein expression may be the useful markers for predicting biological behaviour of GIST.