| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Short Communication |





From the Departments of Pathology*and Medicine,
Division of Hematology/Oncology, Oregon Health and Science University, Portland; and the Portland Veterans Affairs Medical Center, Portland, Oregon
| Abstract |
|---|
|
|
|---|
From a number of follow-up studies it is clear that mutations of KIT exon 11 are the most common type present in GISTs, but that mutations also occur in exons 9, 13, and 17.4-14 The mutations vary from single base pair substitutions to complex deletions/insertions, but they are invariably in-frame and in many cases have been documented to cause activation of the KIT kinase independent of its natural ligand, stem cell factor. Correspondingly, phosphorylated (activated) KIT is detectable in extracts of GISTs (M Heinrich, C Corless, and J Fletcher, manuscript submitted).12 Activation of KIT seems important to the growth of GISTs, because the proliferation of GIST cells in culture is inhibited by the tyrosine kinase inhibitor STI571, a potent blocker of KIT kinase activity.15 Moreover, in recent clinical trials the majority of patients with malignant GIST have shown a benefit to treatment with STI571.16-18
Although the importance of KIT mutations in the biology of GISTs is well established, it remains unclear at what point in the development of these tumors the mutations are acquired. Several studies have suggested that mutations in KIT exon 11 are more common in malignant than in benign GISTs.5,6,14,19,20 In a large series published by Taniguchi and colleagues7 (124 patients), exon 11 mutations were identified in 57% of tumors and seemed to correlate with disease recurrence and shortened survival (86% versus 49% 5-year survival). In contrast, Rubin and colleagues12 did not observe a correlation between KIT mutation status and tumor grade.
In this report we examine the frequency of KIT gene mutations in a series of tumors that were small (10 mm or less), clinically incidental, and morphologically benign. The majority of these lesions, which represent the earliest pathologically recognizable GISTs, were found to harbor mutations of the type frequently identified in larger, malignant lesions. The results favor the view that activating mutations in KIT occur early in the development of GISTs.
| Materials and Methods |
|---|
|
|
|---|
Immunohistochemistry for KIT (CD117) was performed as follows. Sections from the original paraffin blocks were heated in Citra buffer (Biogenex, San Ramon, CA) for 20 minutes in a vegetable steamer (Sunbeam-Oster Household Products, Schaumburg, IL) and then placed on a DAKO automated immunostainer (DAKO Corp., Carpinteria, CA). A standard avidin-biotin staining protocol was performed with the DAKO polyclonal rabbit antibody (DAKO A4502), used at 1:400 dilution, goat biotinylated anti-rabbit secondary (Vector Laboratories, Burlingame, CA), and the Vectastain Elite kit (Vector Laboratories). Endogenous mast cells served as internal-positive controls in all cases; the antibody did not stain other tissue elements (eg, epithelial cells) at the selected titer.
Tumor tissue was identified on unstained, 5 µm sections by comparison with hematoxylin and eosin (H&E)-stained slides and was carefully collected using a clean, sterile scalpel blade into a microfuge tube. Because the tumors were round discrete masses, dissection by this approach was straightforward and there was minimal contamination from adjacent normal muscularis cells (note that such contamination would serve to bias the results toward an apparent wild-type genotype). The dissected tissue was deparaffinized by serial extraction with xylenes and ethanol and allowed to air-dry. DNA was extracted using the Qiagen minikit (no. 51304; Qiagen, Valencia, CA) in accordance with the manufacturers recommendations.
Purified tumor DNA (0.5 µg) was subjected to 45 cycles of polymerase chain reaction (PCR) using the High-Fidelity PCR System (no. 1732078; Roche, Indianapolis, IN). Primer pairs for each exon analyzed are listed in Table 1
. Negative controls were included in every set of amplifications. In a minority of cases there was insufficient amplified DNA for screening by high-pressure liquid chromatography (HPLC) after single step amplification and therefore a second round of amplification was performed using nested primers (Table 1)
.
|
Case 9 was heavily infiltrated by lymphocytes and yielded only a small mutant peak at the nondenaturing temperature when its exon 11 amplimer was analyzed by D-HPLC. Although this peak suggested the presence of a deletion, the quantity of mutant DNA was too small to be confirmed by direct sequencing. Therefore the amplification products were cloned into pCR4-TOPO using the TOPO TA cloning kit (version H; Invitrogen, Carlsbad, CA) and the ligated plasmids were used to transform competent Escherichia coli (OneShot TOP10, Invitrogen). Isolated plasmids were screened for the mutant exon insert by PCR and D-HPLC. Direct sequence analysis of cloned mutant DNA confirmed the presence of an in-frame exon 11 deletion in this case.
| Results and Discussion |
|---|
|
|
|---|
|
|
|
|
The issue of whether KIT mutations are related to the oncological progression of GISTs has been raised in several studies, with differing results. Lasota and co-workers6 found only one exon 11 mutation in 19 benign GISTs (5.2%), whereas 12 of 24 malignant GISTs (50%) harbored detectable mutations. Similarly, Li and colleagues20 reported exon 11 mutations in 3 of 4 borderline tumors and 6 of 10 malignant tumors, but found no mutations in the 2 benign lesions examined. This apparent difference between benign and malignant GISTs was not as pronounced in the study by Debiec-Rychter and colleagues14 that included sequencing of exons 9 and 13. They observed KIT mutations in 3 of 9 (33%) benign tumors and 8 of 14 (57%) malignant tumors.
Using a reverse transcriptase-PCR approach, Rubin and colleagues12 recently documented KIT mutations in 10 of 10 benign GISTs (100%), paralleling the results reported here. Indeed, there was no difference in the KIT mutation frequency among the benign, borderline, and malignant tumors examined by Rubin and colleagues,12 (total 48 cases), and the overall incidence of mutations was strikingly high (92%). The data from this study suggest that technical issues may influence the detection of KIT mutations in genomic DNA, reducing the apparent mutation frequency. In a recent analysis of genomic DNA from 72 malignant GISTs, we used D-HPLC to screen PCR amplimers of the KIT gene and found mutations (sequence-confirmed) in 86% of cases, which is quite close to the frequency observed by Rubin and colleagues17 using reverse transcriptase-PCR. Based on our experience, there are two advantages of using D-HPLC to screen PCR amplimers. First, D-HPLC screening predicts the type of mutation to be expected during DNA sequence analysis. Second, there is increased sensitivity for mutations (<10% mutant DNA can be detected). This is illustrated by case 9, in which a minor peak representing an exon 11 deletion was reproducibly detected but could not be confirmed by direct sequence analysis. Contaminating wild-type DNA from infiltrating lymphocytes likely interfered with the sequence analysis, although it is also possible that only a minority of the tumor cells harbored the mutation. Subcloning of the mutant peak yielded sufficient mutant amplimer to document the in-frame deletion in this case.
In applying the D-HPLC approach to the incidental tumors in this report, we detected exon 11 mutations in 77% (10 of 13), matching the 70% frequency that we observed among the 72 malignant GISTs. Moreover, the overall percentage of KIT mutations in the group of incidental tumors (85%) was essentially identical to that of the malignant GISTs (86%). It has previously been suggested that GISTs harboring an exon 11 mutation have a worse prognosis than tumors without detected mutations.7,19 However, the relatively low overall frequency of KIT mutations observed in these studies (37 to 57%) complicates the interpretation of their findings.
In the course of selecting incidental GISTs for this study, we identified several small leiomyomas of the type recently reviewed by Miettinen and colleagues.22 These lesions, which are often associated with the muscularis mucosae, may have areas of hyalinization and other morphological features that closely resemble low-grade GISTs on H&E stain. Nevertheless, they are immunohistochemically negative for KIT and are usually positive for desmin. We examined one small leiomyoma for KIT mutations and found none (data not shown).
The presence of activating KIT mutations in a high percentage of early, benign GISTs is entirely consistent with the proposal that these mutations represent a gatekeeper alteration that plays a fundamental role in GIST development. It is also consistent with recent studies of four different kindreds in which heritable mutations of KIT exon 11 or 13 have been demonstrated.23-26 In all four kindreds, affected individuals develop multiple GISTs, and in some of these patients there is demonstrable hyperplasia of KIT-positive cells in the area of Auerbachs plexus, consistent with interstitial cells of Cajal.
In summary, we have examined 13 clinically incidental, morphologically benign GISTs that were 10 mm or less in size and found an 85% incidence of mutations in the KIT gene. This high frequency of mutations is strikingly similar to that observed by the same methodology in a larger series of clinically significant GISTs, suggesting that these mutations occur very early in the course of GIST development. Our findings do not support a negative prognostic impact of KIT mutations, as has been proposed in other studies.
| Acknowledgements |
|---|
| Footnotes |
|---|
Supported in part by grants from the Veterans Administration Merit Review Program, the Northwest Health Foundation (to M. C. H.), and the Oregon Cancer Institute (to C. L. C.).
Accepted for publication February 7, 2002.
| References |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
X. Jiang, J. Zhou, N. K. Yuen, C. L. Corless, M. C. Heinrich, J. A. Fletcher, G. D. Demetri, H. R. Widlund, D. E. Fisher, and F. S. Hodi Imatinib Targeting of KIT-Mutant Oncoprotein in Melanoma Clin. Cancer Res., December 1, 2008; 14(23): 7726 - 7732. [Abstract] [Full Text] [PDF] |
||||
![]() |
C.-F. Li, W.-W. Huang, J.-M. Wu, S.-C. Yu, T.-H. Hu, Y.-H. Uen, Y.-F. Tian, C.-N. Lin, D. Lu, F.-M. Fang, et al. Heat Shock Protein 90 Overexpression Independently Predicts Inferior Disease-Free Survival with Differential Expression of the {alpha} and {beta} Isoforms in Gastrointestinal Stromal Tumors Clin. Cancer Res., December 1, 2008; 14(23): 7822 - 7831. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Beadling, E. Jacobson-Dunlop, F. S. Hodi, C. Le, A. Warrick, J. Patterson, A. Town, A. Harlow, F. Cruz III, S. Azar, et al. KIT Gene Mutations and Copy Number in Melanoma Subtypes Clin. Cancer Res., November 1, 2008; 14(21): 6821 - 6828. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. S. Hodi, P. Friedlander, C. L. Corless, M. C. Heinrich, S. Mac Rae, A. Kruse, J. Jagannathan, A. D. Van den Abbeele, E. F. Velazquez, G. D. Demetri, et al. Major Response to Imatinib Mesylate in KIT-Mutated Melanoma J. Clin. Oncol., April 20, 2008; 26(12): 2046 - 2051. [Full Text] [PDF] |
||||
![]() |
A L Gomes, A Gouveia, A F Capelinha, D de la Cruz, P Silva, R M Reis, A Pimenta, and J M Lopes Molecular alterations of KIT and PDGFRA in GISTs: evaluation of a Portuguese series J. Clin. Pathol., February 1, 2008; 61(2): 203 - 208. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. A. Cassier, A. Dufresne, and J.-Y. Blay Controversies in the Adjuvant Treatment of Gastrointestinal Stromal Tumors (GIST) with Imatinib ASCO Educational Book, January 1, 2008; 2008(1): 524 - 528. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. Rutkowski, Z. I. Nowecki, W. Michej, M. Debiec-Rychter, A. Wozniak, J. Limon, J. Siedlecki, U. Grzesiakowska, M. Kakol, C. Osuch, et al. Risk Criteria and Prognostic Factors for Predicting Recurrences After Resection of Primary Gastrointestinal Stromal Tumor Ann. Surg. Oncol., July 1, 2007; 14(7): 2018 - 2027. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Zamo, A. Bertolaso, I. Franceschetti, G. Weirich, P. Capelli, S. Pecori, M. Chilosi, H. Hoefler, F. Menestrina, and A. Scarpa Microfluidic Deletion/Insertion Analysis for Rapid Screening of KIT and PDGFRA Mutations in CD117-Positive Gastrointestinal Stromal Tumors: Diagnostic Applications and Report of a New KIT Mutation J. Mol. Diagn., April 1, 2007; 9(2): 151 - 157. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. R Stewart, C. L Corless, B. P Rubin, M. C Heinrich, L. M Messiaen, L. J Kessler, P. J Zhang, and D. G Brooks Mitotic recombination as evidence of alternative pathogenesis of gastrointestinal stromal tumours in neurofibromatosis type 1 J. Med. Genet., January 1, 2007; 44(1): e61 - e61. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. L. Corless, P. Harrell, M. Lacouture, T. Bainbridge, C. Le, K. Gatter, C. White Jr, S. Granter, and M. C. Heinrich Allele-Specific Polymerase Chain Reaction for the Imatinib-Resistant KIT D816V and D816F Mutations in Mastocytosis and Acute Myelogenous Leukemia J. Mol. Diagn., November 1, 2006; 8(5): 604 - 612. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Bauer, L. K. Yu, G. D. Demetri, and J. A. Fletcher Heat shock protein 90 inhibition in imatinib-resistant gastrointestinal stromal tumor. Cancer Res., September 15, 2006; 66(18): 9153 - 9161. [Abstract] [Full Text] [PDF] |
||||
![]() |
L Tornillo and L M Terracciano An update on molecular genetics of gastrointestinal stromal tumours. J. Clin. Pathol., June 1, 2006; 59(6): 557 - 563. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Martin, A. Poveda, A. Llombart-Bosch, R. Ramos, J. A. Lopez-Guerrero, J. G. del Muro, J. Maurel, S. Calabuig, A. Gutierrez, J. L. G. de Sande, et al. Deletions Affecting Codons 557-558 of the c-KIT Gene Indicate a Poor Prognosis in Patients With Completely Resected Gastrointestinal Stromal Tumors: A Study by the Spanish Group for Sarcoma Research (GEIS) J. Clin. Oncol., September 1, 2005; 23(25): 6190 - 6198. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. L. Corless, A. Schroeder, D. Griffith, A. Town, L. McGreevey, P. Harrell, S. Shiraga, T. Bainbridge, J. Morich, and M. C. Heinrich PDGFRA Mutations in Gastrointestinal Stromal Tumors: Frequency, Spectrum and In Vitro Sensitivity to Imatinib J. Clin. Oncol., August 10, 2005; 23(23): 5357 - 5364. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. P. Rubin, C. R. Antonescu, J. P. Scott-Browne, M. L. Comstock, Y. Gu, M. R. Tanas, C. B. Ware, and J. Woodell A Knock-In Mouse Model of Gastrointestinal Stromal Tumor Harboring Kit K641E Cancer Res., August 1, 2005; 65(15): 6631 - 6639. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. P. Li, J. A. Fletcher, M. C. Heinrich, J. E. Garber, S. E. Sallan, C. Curiel-Lewandrowski, A. Duensing, M. van de Rijn, L. E. Schnipper, and G. D. Demetri Familial Gastrointestinal Stromal Tumor Syndrome: Phenotypic and Molecular Features in a Kindred J. Clin. Oncol., April 20, 2005; 23(12): 2735 - 2743. [Abstract] [Full Text] [PDF] |
||||
![]() |
J.-Y. Blay, S. Bonvalot, P. Casali, H. Choi, M. Debiec-Richter, A. P. Dei Tos, J.-F. Emile, A. Gronchi, P. C. W. Hogendoorn, H. Joensuu, et al. Consensus meeting for the management of gastrointestinal stromal tumors * Report of the GIST Consensus Conference of 20-21 March 2004, under the auspices of ESMO Ann. Onc., April 1, 2005; 16(4): 566 - 578. [Abstract] [Full Text] [PDF] |
||||
![]() |
U. De Giorgi and J. Verweij Imatinib and gastrointestinal stromal tumors: Where do we go from here? Mol. Cancer Ther., March 1, 2005; 4(3): 495 - 501. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. Sihto, M. Sarlomo-Rikala, O. Tynninen, M. Tanner, L. C. Andersson, K. Franssila, N. N. Nupponen, and H. Joensuu KIT and Platelet-Derived Growth Factor Receptor Alpha Tyrosine Kinase Gene Mutations and KIT Amplifications in Human Solid Tumors J. Clin. Oncol., January 1, 2005; 23(1): 49 - 57. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. L. Corless, L. McGreevey, A. Town, A. Schroeder, T. Bainbridge, P. Harrell, J. A. Fletcher, and M. C. Heinrich KIT Gene Deletions at the Intron 10-Exon 11 Boundary in GI Stromal Tumors J. Mol. Diagn., November 1, 2004; 6(4): 366 - 370. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. D. Demetri, R. L. Titton, D. P. Ryan, and C. D.M. Fletcher Case 32-2004 - A 68-Year-Old Man with a Large Retroperitoneal Mass N. Engl. J. Med., October 21, 2004; 351(17): 1779 - 1787. [Full Text] [PDF] |
||||
![]() |
S Carvalho, A O e Silva, F Milanezi, S Ricardo, D Leitao, I Amendoeira, and F C Schmitt c-KIT and PDGFRA in breast phyllodes tumours: overexpression without mutations? J. Clin. Pathol., October 1, 2004; 57(10): 1075 - 1079. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. L. Corless, J. A. Fletcher, and M. C. Heinrich Biology of Gastrointestinal Stromal Tumors J. Clin. Oncol., September 15, 2004; 22(18): 3813 - 3825. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. B. West, C. L. Corless, X. Chen, B. P. Rubin, S. Subramanian, K. Montgomery, S. Zhu, C. A. Ball, T. O. Nielsen, R. Patel, et al. The Novel Marker, DOG1, Is Expressed Ubiquitously in Gastrointestinal Stromal Tumors Irrespective of KIT or PDGFRA Mutation Status Am. J. Pathol., July 1, 2004; 165(1): 107 - 113. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. L. Eisenberg and I. Judson Surgery and Imatinib in the Management of GIST: Emerging Approaches to Adjuvant and Neoadjuvant Therapy Ann. Surg. Oncol., May 1, 2004; 11(5): 465 - 475. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. W. Kim, H. Lee, Y.-K. Kang, M. S. Choe, M.-H. Ryu, H. M. Chang, J. S. Kim, J. H. Yook, B. S. Kim, and J. S. Lee Prognostic Significance of c-kit Mutation in Localized Gastrointestinal Stromal Tumors Clin. Cancer Res., May 1, 2004; 10(9): 3076 - 3081. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Kemmer, C. L. Corless, J. A. Fletcher, L. McGreevey, A. Haley, D. Griffith, O. W. Cummings, C. Wait, A. Town, and M. C. Heinrich KIT Mutations Are Common in Testicular Seminomas Am. J. Pathol., January 1, 2004; 164(1): 305 - 313. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. C. Heinrich, C. L. Corless, G. D. Demetri, C. D. Blanke, M. von Mehren, H. Joensuu, L. S. McGreevey, C.-J. Chen, A. D. Van den Abbeele, B. J. Druker, et al. Kinase Mutations and Imatinib Response in Patients With Metastatic Gastrointestinal Stromal Tumor J. Clin. Oncol., December 1, 2003; 21(23): 4342 - 4349. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. Cruz III, B. P. Rubin, D. Wilson, A. Town, A. Schroeder, A. Haley, T. Bainbridge, M. C. Heinrich, and C. L. Corless Absence of BRAF and NRAS Mutations in Uveal Melanoma Cancer Res., September 15, 2003; 63(18): 5761 - 5766. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. R. Antonescu, G. Sommer, L. Sarran, S. J. Tschernyavsky, E. Riedel, J. M. Woodruff, M. Robson, R. Maki, M. F. Brennan, M. Ladanyi, et al. Association of KIT Exon 9 Mutations with Nongastric Primary Site and Aggressive Behavior: KIT Mutation Analysis and Clinical Correlates of 120 Gastrointestinal Stromal Tumors Clin. Cancer Res., August 1, 2003; 9(9): 3329 - 3337. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Rosai GIST: An Update International Journal of Surgical Pathology, July 1, 2003; 11(3): 177 - 186. [PDF] |
||||
![]() |
R. Schneider-Stock, C. Boltze, J. Lasota, M. Miettinen, B. Peters, M. Pross, A. Roessner, and T. Gunther High Prognostic Value of p16INK4 Alterations in Gastrointestinal Stromal Tumors J. Clin. Oncol., May 1, 2003; 21(9): 1688 - 1697. [Abstract] [Full Text] [PDF] |
||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |