| Objective: To investigate c-kit gene mutation characteristics in gastrointestinal stromal tumors relationship between biological behavior and prognosis, provide guidance for clinical diagnosis and treatment.Methods: to do genetic testing for the 119 cases of GIST patients with pathological and immunohistochemical were confirmed in our hospital outpatient and hospitalization during October 2014 to October 2004.Using DNA extracted,PCR amplification and gene sequencing to detect tumor tissue’s exon mutation Features of 9,11,13,17 c-kit gene. Followed by telephone follow-up, outpatient review records.Analysis the relationship between prognosis of patients with c-kit gene mutation and the biological behavior of GIST. Using SPSS13.0 statistical software for statistical analysis, application of Kaplan Meier limit multiplication to calculate survival and recurrence rate. After statistics treatment results with P<0.05 for statistical significance.Results: 1 General Information 1.1 119 cases of GIST patients who were pathological and immunohistochemical confirmed in our hospital outpatient and hospitalization during October 2014 to October 2004. 1.2 gender: 119 cases of GIST patients 65 cases of the men and women in 54 cases. The sex ratio is: 1.2:1. 1.3 Age: The range of age is 23-81 years, with a median age of 55.0 years old, 59 cases of patients with less than 55 years of age, 60 patients with greater than or equal to 55 years of age. 1.4 Time of onset: ranging from 6 hours to 11 years. 1.5 main complaint and signs: Whether onset, recurrence, GIST patients aftertransfered had no significant clinical specificity include abdominal discomfort, abdominal pain, palpable abdominal mass, vomiting, black stools, fatigue, localized tenderness, anemia. 1.6 There are 40 patients with a past medical history(while 23 cases of patients with hypertension, 15 cases with a history of abdominal surgery), with no previous history of 79 cases. 1.7 operation situation: radical resection of 110 cases, 9 cases of palliative resection(including in our hospital of 47 cases of surgery, the outer court line operation of 71 cases). 1.8 taking imatinib preoperative 1 case. 2 The biological characteristics of GIST 2.1 GIST primary site Occur in the stomach: 46 cases(38.66%), duodenum: 6 cases(5.04%), ileum 42 cases(35.29%), colorectal: 5 cases(4.20%), parenteral: 20 cases(16.81%). 2.2 longest tumor diameter: the longest tumor diameter ≤5cm 16 cases(13.45%), the longest tumor diameter between 5.1cm-10 cm 45 cases(37.82%), the longest tumor diameter(48.74%)>10cm 58 cases. 2.3 Immunohistochemistry: CD117 detected as positive 117 cases(98.32%) and negative in two cases, but tested positive for CD34; CD34 weretested positive 95 cases(79.83%); DOG-1 tested positive were 55 cases(46.22%), Vim detected as positive in 49 cases(41.18%). 2.4 mitotic index: 119 cases of GIST patients mitotic count ≤5/50 HPF were 48 cases(40.34%), mitotic count >5/50 HPF 71 cases(59.66%). 2.5 GIST risk classification: improved risk classification according to NIH criteria: one case of very low risk, low risk of 9 cases, 18 cases of moderate risk, high risk of 91 cases. 3 Gene types of GIST Gene types were detected in 119 patients with GIST c-kit gene mutation 105 cases(88.24%), PDGFRA mutations detected in 1 case(0.84%), the wildtype in 13 cases(10.92%).3.1 c-kit gene mutation Immunohistochemistry showed positive for CD117, which c-kit11 mutation in exon 94 cases(89.52%, 94/105); c-kit9 exon 9 patients(8.57%, 9/105); ckit13 exon 1 case(0.95%, 1/105); c-kit17 exon 1 case(0.95%, 1/105). Detects the c-kit gene mutations in 105 cases the proportion of CD117-positive GIST cases up to 89.74%(105/117). 3.1.1 c-kit11 mutant type No.11 c-kit gene exon is the most common mutation sites, mutant forms include: deletions, point mutations and insertion mutations(tandem repeats), accounting for c-kit11 exon mutations of 62.77%(59 / 94), 36.17%(34/94), 1.06%(1/94).GIST genes which 48 patients(51.6%, 48/94) focused on mutations in the 5 ’end of the first codon 550-560 region, namely a "hot spot" area.The most common mutation occurs in the form of the 5 ’codon of the 557-558 WK(Trp-Lys) deletion mutation, accounting for 10.64%(10/94), followed occurred in codon 559 point mutations and deletions mutation, accounting for 6.38%(6/94), 4.26%(4/94). There are 6.38%(6/94) of the gene mutation occurs in the 3 ’codon of the vicinity of 570-580. 3.1.2 c-kit9 mutant type Detects the c-kit gene No. 9 mutation in exon 9 cases(8.57%, 9/105), of which 7 were for the 502 and 503 codons alanine(Ala) and tyrosine(Try) 6 nucleotides(GCCTAT) tandem repeat insertional mutagenesis.7 Example 6 cases occurred in the jejunum and ileum, one case occurred in the rectum. 3.1.3 c-kit13 and 17 mutant type C-kit gene mutation were detected in No. 13 and 17 1 case(1.06%, 1/94), performed as the 642 codon(K642E) point mutations, the 822 codon(N822K) point mutations. 3.2 PDGFRA gene mutation 1 case was detected with PDGFRA mutations(7.14%, 1/14), accounting for 0.84% of the total number of cases(1/119). Its mutated form No. 18 PDGFRA exon mutation, the mutation site for the codon 842 point mutation(D842V) in 14 cases of non-c-kit gene mutations patients with GIST.3.3 wild-type The wild-type were detected in 13 cases, accounting for 10.93% of the total. 4 Follow-up situations Follow-up time: The deadline for December 2014, 2-122-month follow-up period. 4 cases were lost, and the remaining GIST patients successfully followed up,the rate is 96.64%(115/119). 4.1 Taking Gleevec condition assessment of the situation 119 cases of GIST patients taking Gleevec before surgery in 1 case, radical surgery taking Gleevec were 73 cases of recurrence and metastasis after taking Gleevec were 45 cases(both Gleevec dose 400mg/day). There are 52 cases of recurrence(including two cases of lost persons) accounted for 43.70%, of which 21 patients had stable disease(40.39%), disease remission(including partial remission and complete remission) were 20 cases(38.46%), disease progression(including death) in 11 cases(21.15%); no clear recurrence 67 cases(including two cases of lost persons) accounted for 56.30%. Success followed up 115 patients, stable disease were 79 cases(68.70%), disease remission(including partial remission and complete remission) were 24 cases(20.87%), disease progression(including death) in 12 cases(10.43%), The overall benefit rate of 89.57%. c-kit9 patients with mutations in two cases instead sunitinib(Sutent), 7 patients taking imatinib mesylate(Gleevec). c-kit11 gene mutation patients, 94 cases were taking imatinib mesylate(Gleevec). c-kit13,17 and PDGFRA patients were taking one each imatinib mesylate(Gleevec). Wild-type 13 cases were taking imatinib mesylate(Gleevec). The c-kit9,11 patients with wild-type tumor-free survival analysis, judgment-free survival time(χ2 = 6.685, P = 0.035). 4.2 GIST recurrence and metastasis: In follow-up, 4 cases were dead due to recurrence. There are 52 cases with recurrence and metastasis, and 67 cases without. Of which 12 cases werelocal recurrence and 40 cases were distant metastasis.Local recurrence sites were: two cases of stomach, jejunum and ileum three cases, two cases of colorectal, parenteral five cases. Metastatic sites were: liver, 20 cases, 11 cases of abdominal and pelvic, abdominal and pelvic liver and abdominal organs merge five cases, one case of peritoneum, omentum one case, retroperitoneal one case, one case around the rectum. 4.3 recurrence rate 1-year recurrence occurs in 22 cases, 3-year recurrence occurs in 17 cases, 5-year recurrence occurs in 13 cases. 1,3,5 recurrence rates were 18.49%, 14.29%, 12.61%. 4.4 disease-free survival(PFS) Free survival time of 0-72 months, with a median disease-free survival time of: 12.0 months, the average survival time of 17.72 months. 1-year disease-free survival rate of 80.0%, 3-year disease-free survival rate was 32.17%, 5-year disease-free survival rate of 7.83%. 4.5 Lifetime 1-year survival of 114 cases, 68 cases survived three years, five years survival of 35 cases, overall survival(OS): survival time ranged from 1-149 months, with an average survival time was 42.67 months, median survival time was 35 months. 1,3,5 survival rates were: 95.80%, 57.14%, 29.41%. 5 Gene mutation relationship with the biological behavior of GIST 5.1 The relationship between gene mutation rate overall and the biological behavior of GIST The group sex(χ2=3.350, P=0.067), age(χ2 = 1.373, P=0.241), parts(χ2 = 9.238, P=0.055), mitotic index(χ2=0.518, P=0.427), recurrent metastasis(χ2 =2.522, P=0.112), recurrent metastatic sites(χ2=5.072, P=0.167), postoperative pathology without bleeding and necrosis(χ2=0.207, P=0.649) for GIST was no significant difference in the overall mutation rate; The maximum diameter(χ2=6.140, P=0.046), risk stratification(χ2=11.751, P=0.003) for GIST overall mutation rate difference was statistically significant. 5.2 The relationship between c-kit 11 gene mutation rate and the biologicalbehavior of GIST The group sex(χ2=0.560, P=0.454), parts(χ2=1.810, P=0.771), mitotic index(χ2=1.167, P=0.280), relapse metastasis(χ2=0.176, P=0.675), relapse metastatic sites(χ2=2.585, P=0.460),whether postoperative pathology bleeding or necrosis(χ2=0.289, P=0.591), risk stratification(χ2=3.314, P=0.191) effect on c-kit11 no statistical differences in mutation rate significance; age(χ2=4.296, P=0.038), maximum diameter(χ2=6.637, P=0.036) differences affect c-kit11 mutation rate was not statistically significant. 5.3 The relationship between c-kit11 mutated form and the biological behavior of GIST Primary site, tumor diameter size, mitotic index number, whether recurrence, recurrence site, pathological or without hemorrhage and necrosis on GIST mutant forms of c-kit11 no significant difference; and risk stratification(χ2=11.544, P=0.003) for the c-kit11 GIST deletion mutation was statistically significant. 6 Gene mutation relationship with prognosis 119 cases of GIST patients studied in this group underwent surgery plus combined treatment with imatinib, and its genetic testing, c-kit gene mutations occur 105 cases, PDGFRA gene mutations occur 1 case.13 cases without gene mutation, respectively, and the gene mutation occurs not appear GIST patients with mutations in 1,3,5-year disease-free survival and recurrence rates were statistically analyzed and showed that mutations occur in patients with mutations did not appear free survival and recurrence rate was no significantly different, was not statistics significance(P>0.05). 7 c-kit gene and non-c-kit gene influence on disease-free survival time and time to relapse The 119 cases were divided into c-kit gene group and non-c-kit genome analysis of disease-free survival, as shown in(Fig7, Fig.8), the non-c-kit gene mutation than c-kit gene mutation late recurrence.(χ2=104.337,P=0.000)Conclusions: 1 In this study, genetic testing GIST c-kit gene mutation rate was the highest(88.24%), followed by the wild-type(10.92%), while the lowest PDGFRA mutation(0.84%). 2 In the c-kit gene mutations the highest rate of mutation is c-kit11 gene(89.52%), followed by c-kit9 gene(8.57%), c-kit13 and c-kit17 lowest(0.95%). mutant types of c-kit11 from more to less are missing mutations(62.77%), point mutations(36.17%), insertion mutation(1.06%). 3 C-kit 11 gene mutation rate related to age and tumor longest diameter. The older, larger of the tumor appeared c-kit11 higher mutation probability. 4 C-kit11 mutation rate has no correlation with sex, tumor location, mitotic index, risk stratification, recurrence and metastasis, the recurrence of metastatic sites, hemorrhage and necrosis. 5 C-kit9 gene mutated type with the higher risk of NIH appears greater the probability of c-kit11 deletion mutations. And has no correlation with GIST site, mitotic index, relapse metastasis, recurrence site, bleeding and necrosis. 6 C-kit9 mutation rate and sex, age, tumor location, mitotic index, risk stratification, recurrence and so no correlation. 7 The c-kit gene mutations has no correlation with prognosis of GIST patients. 8 Non-c-kit gene mutation relapse later than c-kit gene mutation appears. 9 GIST patients treated with imatinib mesylate(Gleevec) free survival longest wild-type, followed by c-kit11 mutations in patients with non-mutated c-kit9 shortest survival time. |
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