Adult ; Exons ; Female ; Gastrointestinal Stromal Tumors ; genetics ; metabolism ; pathology ; Gene Deletion ; Humans ; Proto-Oncogene Proteins c-kit ; genetics ; metabolism

Gastrointestinal stromal tumors (GISTs) of the gallbladder are representative of an extremely rare group of tumors. We have encountered a patient with a malignant GIST of the gallbladder and presented it with a review of some articles. A 72-yr-old woman initially presented with right upper quadrant abdominal pain, fever and chills. Emergency cholecystectomy was performed under the impression of gallbladder empyema. Liver metastasis was found at 7 months postoperatively and the patient expired 9 months after the surgery. At the time of cholecystectomy, the gallbladder showed a necrotic serosal surface with an irregular thickened wall. A mass, 6 cm in length and 3 cm in width, encircled the whole wall of the neck and upper body of the gallbladder. Microscopic findings revealed frequent mitotic figures (more than 20/50 HPF) and tumor necrosis. Hyperchromatic, pleomorphic and spindle shaped neoplastic cells that were arranged in a pattern of short fascicles infiltrated the entire layer of the gallbladder. The tumor cells were immunoreactive for CD117 antigen (c-kit protein) and vimentin. They were negative for desmin, smooth muscle actin and S-100 protein. Mutations of the c-kit proto-oncogene were not found in this case. These findings were sufficient to provide enough clinical, histopathological and immunohistochemicalevidence in diagnosing our case as a malignant GIST.
Aged ; Female ; Gallbladder Neoplasms/genetics/metabolism/*pathology ; Gastrointestinal Stromal Tumors/genetics/metabolism/*pathology ; Humans ; Proto-Oncogene Protein c-kit/genetics/metabolism

OBJECTIVETo investigate the expression of phospho-platelet derived growth factor receptor alpha (P-PDGFR-alpha) in gastrointestinal stromal tumors (GIST) and extra-gastrointestinal stromal tumors (EGIST) and its clinical significance.

METHODSExpression of P-PDGFR-alpha in 28 samples of positive CD117 and 13 samples of negative CD117 was detected by Envision immunohistochemical staining. Direct PCR sequencing was used to investigate the mutation status of c-kit gene exons 9, 11, 13, 17 and PDGFR-alpha gene exons 12 and 18.

RESULTSThe positive rate of P-PDGFR-alpha expression in GISTs with negative CD117 was 69.2%, which was significantly higher than that in GISTs with positive CD117 (7.1%, P<0.05). The positive rates of P-PDGFR-alpha expression in epithelioid GISTs(27.3%) and mixed GIST(63.3%) were both significantly higher than that in fusiform GISTs (9%, P<0.05). The positive rate of CD117 expression in fusiform GISTs (53.6%)was significantly higher than that in epithelioid GISTs (7.1%) and mixed GISTs(39.3%, P<0.05). C-kit gene mutation was found in 19 GIST cases with positive CD117. C-kit gene mutation was found in 19 of 28 GIST patients with positive CD117, among them, mutation of exon 11 occurred in 15 cases and exon 13 in 4 cases. No C-kit gene mutation was seen in 13 GIST patients with negative CD117. PDGFR-alpha gene mutation was found in 4 of 11 GIST cases with positive P-PDGFR-alpha and all occurred in exon 18.

CONCLUSIONSExamination of P-PDGFR-alpha expression may provide reliable evidence for the further improvement of pathological diagnosis,pathological typing and treatment for GISTs with negative CD117. Phosphorylated protein induced by PDGFR-alpha mutation may be associated with the important alternative molecular mechanism and the biological behavior of GIST development.

Adolescent ; Adult ; Aged ; Exons ; Female ; Gastrointestinal Stromal Tumors ; genetics ; pathology ; Gastrointestinal Tract ; pathology ; Humans ; Male ; Middle Aged ; Mutation ; Oxidative Phosphorylation ; Proto-Oncogene Proteins c-kit ; genetics ; metabolism ; Receptor, Platelet-Derived Growth Factor beta ; genetics ; metabolism ; Young Adult

OBJECTIVEGastrointestinal stromal tumors (GISTs) have a broad spectrum of biological behaviors ranging from benign, borderline and malignant. This study aimed to screen differentially expressed microRNAs (miRNAs) between malignant and borderline GISTs and to investigate the potential role of miRNAs in the malignant transformation of GISTs.

METHODSSix GIST samples including borderline tumors (n = 3) and malignant tumors (n = 3) were collected based on the clinical and pathological characteristics. Total RNA was extracted, followed by miRNA microarray analysis to screen the differentially expressed miRNAs. The most significantly expressed 4 miRNAs were then chosen for further validation by real-time PCR in 22 additional GIST samples.

RESULTSDirect comparison of malignant group versus borderline group revealed 14 significantly and differentially expressed miRNAs (P < 0.05, with a fold change of < 0.5 or > 2). Five miRNAs were up-regulated and nine were down-regulated in the malignant group. Four miRNAs (miR-221, miR-135b, miR-675(*) and miR-218) were most significantly and differentially expressed between the two groups. The differential expression of 2 miRNAs (miR-221 and miR-675(*)) were subsequently confirmed with good concordance by real-time PCR.

CONCLUSIONSThe differential miRNA expression profiles between two groups are revealed by miRNA microarray assay, and confirmed by real-time PCR. Among differentially expressed miRNAs, miR-221 and miR-675(*) might be related to the malignant transformation of GISTs, and have a potential value in predicting biological behavior of GISTs.

Adult ; Aged ; Aged, 80 and over ; Cell Transformation, Neoplastic ; Down-Regulation ; Female ; Gastrointestinal Neoplasms ; genetics ; pathology ; Gastrointestinal Stromal Tumors ; genetics ; pathology ; Gene Expression Profiling ; Humans ; Male ; MicroRNAs ; genetics ; metabolism ; Microarray Analysis ; Middle Aged ; Real-Time Polymerase Chain Reaction ; Up-Regulation

Antigens, CD34 ; metabolism ; Carcinoma, Signet Ring Cell ; genetics ; metabolism ; pathology ; surgery ; Codon ; Diagnosis, Differential ; Exons ; Female ; Follow-Up Studies ; Gastrectomy ; methods ; Gastrointestinal Neoplasms ; genetics ; metabolism ; pathology ; surgery ; Gastrointestinal Stromal Tumors ; genetics ; metabolism ; pathology ; surgery ; Humans ; Melanoma ; metabolism ; pathology ; Middle Aged ; Neurilemmoma ; metabolism ; pathology ; Point Mutation ; Proto-Oncogene Proteins c-kit ; metabolism ; Receptor, Platelet-Derived Growth Factor alpha ; genetics ; metabolism

OBJECTIVETo establish and characterize imatinib-resistant gastrointestinal stromal tumor (GIST) xenografts. Further provided an ideal experimental platform through the imatinib-resistant GIST xenografts to investigate the mechanism of resistance to imatinib.

METHODSImatinib-resistant GIST cells were injected under the skin of athymic nude mice to establish animal models of human imatinib-resistant GIST. The molecular and histopathologic features of GIST xenografts were also analysed and compared with their counterpart of cell lines.

RESULTSThe xenograft tumor models had been established by subcutaneously injection of GIST cells into nude mice. Immunohistochemistry results showed CD117 expression was positive in GIST-PR2 xenograft tumor, but negative in GIST-R. In GIST-PR1, tumor areas showing rhabdomyoblastic differentiation were presented next to areas with classic GIST morphology. The rhabdomyoblastic component demonstrated consistently positivity for desmin and myogenin, whereas CD117 was completely negative. The mutation profiles of these xenograft tumors were the same as their counterpart of cell lines.

CONCLUSIONSHuman GIST xenografts with mutation in c-kit have been established from imatinib-resistant GIST lines. Those models will enable further studies on mechanisms of resistance, combination therapies and allow testing of novel targeted therapies.

Animals ; Antineoplastic Agents ; pharmacology ; Benzamides ; Cell Differentiation ; Cell Line, Tumor ; Desmin ; metabolism ; Drug Resistance, Neoplasm ; Female ; Gastrointestinal Neoplasms ; genetics ; metabolism ; pathology ; Gastrointestinal Stromal Tumors ; genetics ; metabolism ; pathology ; Humans ; Imatinib Mesylate ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Mutation ; Myogenin ; metabolism ; Piperazines ; pharmacology ; Proto-Oncogene Proteins c-kit ; genetics ; metabolism ; Pyrimidines ; pharmacology ; Rhabdomyosarcoma ; metabolism ; pathology ; Xenograft Model Antitumor Assays

OBJECTIVETo evaluate the impact of loss of heterozygosity (LOH) at chromosome 9p21 and P16(INK4A)(CDKN2A) expression on the prognosis of gastrointestinal stromal tumor (GIST).

METHODSA total of 51 cases with GISTs were characterized by immunohistochemistry and evaluated for LOH at 9p21 by microsatellite analysis in 4 markers(D9S1751, D9S1846, D9S942 and D9S1748). Associations of LOH at 9p21 and P16(INK4A) expression encoded by CDKN2A with clinicopathological parameters and prognosis in GISTs were analyzed.

RESULTSThe frequency of 9p21 LOH was 37.0% (10/27) at D9S1751, 37.5%(12/32) at D9S1846, 42.1%(16/38) at D9S942 and 24.2%(8/33) at D9S1748. The overall frequency of LOH at 9p21 was 63.3%(31/49). In 21 samples of 51 GISTs(41.2%), P16 expression was not detected. Loss of P16 expression was 60%(12/20) in high risk group and 23.5%(4/17) in very low and low risk groups(P<0.05). The 5-year overall survival rate of p16-negative patients was 70.8%, while in P16-positive patients it was 92.0%(P<0.05).

CONCLUSIONSLOH at 9p21 is a frequent event in GIST. Loss of CDKN2A gene at 9p21 may contribute to the progression and malignant transformation of GIST. P16 expression in GIST is associated with prognosis.

Adult ; Aged ; Aged, 80 and over ; Chromosomes, Human, Pair 9 ; genetics ; Cyclin-Dependent Kinase Inhibitor p16 ; metabolism ; Female ; Gastrointestinal Stromal Tumors ; genetics ; metabolism ; pathology ; Genes, p16 ; Humans ; Loss of Heterozygosity ; Male ; Microsatellite Repeats ; Middle Aged

OBJECTIVETo study the methylation status of P16 gene promoter and the expression of P16 protein in gastrointestinal stromal tumors(GIST) and to explore the prognostic value.

METHODSMethylation status of the P16 promoter was detected by methylation- specific polymerase chain reaction (MSP) and the expression of P16 protein by immunohistochemistry in 62 patients with GIST.

RESULTSThe status of P16 gene methylation and the expression of P16 protein were significantly different among the patients with different subclassification of GIST using Fletcher's scheme (P < 0.05, P < 0.01). And there were significant differences in progressive disease (PD) among various levels of P16 expression (P < 0.01). P16 gene methylation was closely related to P16 protein. P16 gene methylation accounted for 75% in the tumor tissue with less than 50% P16 positive cells, and accounted for only 10% in the tumor tissue with more than 50% P16 positive cells (P< 0.01).

CONCLUSIONP16 immunohistochemical assessment can be used as a prognostic index for GIST. The patients with more than 50% fraction of cells with low P16 immunostaining have poor prognosis.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; CpG Islands ; Cyclin-Dependent Kinase Inhibitor p16 ; genetics ; metabolism ; DNA Methylation ; Female ; Follow-Up Studies ; Gastrointestinal Stromal Tumors ; genetics ; metabolism ; pathology ; Humans ; Male ; Middle Aged ; Prognosis ; Young Adult

OBJECTIVETo explore the effect of malignant transformation of the L839P, a new mutation site of the PDGFRA gene, on the pathogenesis of gastrointestinal stromal tumors.

METHODSAll recombinant plasmids were stably transfected into CHO cells by liposomes. Western blotting was used to detect the expression of PDGFRA protein. The cell growth curve was plotted by cell counting. Flow cytometry was used to detect the cell cycle and apoptosis of CHO cell, respectively. The stably transformed cells were inoculated subcutaneously into the back of nude mice and the mice were used to observe the tumorigenesis. Transient transfection of the mutant-type plasmids of PDGFRA gene and the wild-type plasmids of kit gene into the CHO cells was performed. Western blot was used to detect the expression of kit protein and its phosphorylated forms.

RESULTSPDGFRA protein expressed in the negative control, experimental group and positive control, except the empty vector. The growth curve showed that it was accelerated in the experimental group and positive control. The ratios of cells in proliferative phase were 28.4% (blank), 24.5% (negative control), 43.8% (experimental group) and 40.9% (positive control). Their apoptotic indexes were 1.8%, 1.9%, 1.5% and 1.6%, respectively. After three weeks, tumors were observed in the nude mice of experimental group and positive control, inoculated with the stably transformed cells. Moreover, the expression of phosphorylated protein of kit was enhanced after cotransfection of the mutant-type plasmids of PDGFRA and the wild-type plasmid of kit.

CONCLUSIONThe PDGFRA mutant L839P is a gain-of-function mutation and has obviously malignant transforming effect on normal cells, and may activate kit protein accelerating the tumorigenesis. Gastrointestinal stromal tumors;

Animals ; Apoptosis ; CHO Cells ; Cell Cycle ; Cell Proliferation ; Cell Transformation, Neoplastic ; Cricetinae ; Cricetulus ; Gastrointestinal Stromal Tumors ; etiology ; genetics ; pathology ; Mice ; Mice, Nude ; Mutation ; Plasmids ; Proto-Oncogene Proteins c-kit ; metabolism ; Receptor, Platelet-Derived Growth Factor alpha ; genetics ; metabolism ; Transfection

Over the past 60 years, investigators of basic science, pathology, and clinical medicine have studied gastrointestinal stromal tumor (GIST) and made minor advances in patient care. Recent discoveries have led to an understanding of the biological role of KIT and platelet-derived growth factor receptor-α in GIST and the development of the tyrosine kinase inhibitor imatinib mesylate (Gleevec, formerly STI-571), one of the most exciting examples of targeted therapy to date. The success of targeted therapy in GIST has lead to new developments in our understanding of the medical and surgical management of the disease. Intense study of GIST may lead to new paradigms in the management of cancer.
Antineoplastic Agents ; therapeutic use ; Benzamides ; Combined Modality Therapy ; Drug Delivery Systems ; Gastrointestinal Neoplasms ; drug therapy ; genetics ; pathology ; surgery ; Gastrointestinal Stromal Tumors ; drug therapy ; genetics ; pathology ; surgery ; Humans ; Imatinib Mesylate ; Mutation ; Piperazines ; therapeutic use ; Protein Kinase Inhibitors ; therapeutic use ; Proto-Oncogene Proteins c-kit ; genetics ; metabolism ; Pyrimidines ; therapeutic use ; Receptor, Platelet-Derived Growth Factor alpha ; genetics ; metabolism