Aged ; Antineoplastic Agents ; therapeutic use ; Benzamides ; therapeutic use ; Drug Resistance, Neoplasm ; Exons ; Gastrectomy ; methods ; Gastrointestinal Neoplasms ; drug therapy ; metabolism ; pathology ; surgery ; Gastrointestinal Stromal Tumors ; drug therapy ; metabolism ; pathology ; surgery ; Humans ; Imatinib Mesylate ; Liver Neoplasms ; drug therapy ; secondary ; Male ; Piperazines ; therapeutic use ; Point Mutation ; Proto-Oncogene Proteins c-kit ; genetics ; metabolism ; Pyrimidines ; therapeutic use

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

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

This study investigated the expression and clinicopathological significance of CD9 in gastrointestinal stromal tumor (GIST). Immunohistochemistry staining for CD9 was performed on tumor tissues from 74 GIST patients. The correlation with clinicopathological features, risk classification and prognosis was analyzed. CD9-positive staining comprised 59.5% (44/74) of the GIST patients. The CD9-positive expression rate of the sample was significantly associated with diameter (P = 0.028), mitotic counts (P = 0.035), risk classification (P = 0.018) and three-year recurrence-free survival (RFS) (P < 0.001). Cox proportional hazards regression (HR = 0.352; P = 0.015) showed that CD9 is an independent factor for post-operative RFS. The subgroup analysis showed that CD9 expression in gastric stromal tumor (GST) is significantly associated with diameter (P = 0.031), risk classification (P = 0.023) and three-year RFS (P = 0.001). The Cox proportional hazards regression (HR = 0.104; P = 0.006) also showed that CD9 is an independent factor for RFS of GST. However, CD9 expression does not have a statistically significant correlation with clinicopathological features, risk classification, and prognosis in non-GST. In conclusion, CD9 expression in GIST appears to be associated with the recurrence and/or metastasis of GIST patients, especially in GST, which may indicate the important role of CD9 in the malignant biological behavior and prognosis of GST.
Adult ; Aged ; Aged, 80 and over ; Antigens, CD9/*genetics/*metabolism ; Disease-Free Survival ; Female ; Gastrointestinal Neoplasms/metabolism/mortality/*pathology ; Gastrointestinal Stromal Tumors/metabolism/mortality/*pathology ; *Gene Expression Regulation, Neoplastic ; Humans ; Immunohistochemistry ; Kaplan-Meier Estimate ; Male ; Middle Aged ; Prognosis ; Proportional Hazards Models ; Risk Factors

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 study the clinical and pathologic features of gastric schwannomas.

METHODSThe macroscopic and microscopic features of 9 cases of gastric schwannoma were analyzed. Immunohistochemical study for S-100 protein, CD117, CD34, neurofilament, desmin, nestin, glial fibrillary acidic protein, platelet derived growth factor-alpha (PDGFR-α) and vimentin was carried out. Mutation analysis of c-kit gene (exon 9, 11, 13 and 17) and PDGFR-α gene (exon 12 and 18) in 1 case was examined by PCR amplification and direct sequencing.

RESULTSThe patients included 5 males and 4 females. The age of patients ranged from 42 to 81 years (median = 56.5 years). The size of the tumors ranged from 2 to 9 cm in greatest diameter. Follow-up data in 8 cases (from 1 month to 65 months) showed no evidence of recurrence or metastasis. Gross examination showed that gastric schwannomas were homogeneous, firm, yellow-white and bore no true fibrous capsule. Histologically, all cases were composed of fascicles of spindle cells associated with nuclear palisading, Verocay body formation and peripheral cuff of reactive lymphoid aggregates. Some of them showed degenerative changes including cyst formation, calcification, hemorrhage, necrosis and hyalinization. Immunohistochemical study showed that the tumor cells were strongly positive for S-100 protein and vimentin. There was various degree of staining for nestin (8/9) and glial fibrillary acidic protein (6/9). They were negative for CD117, CD34, neurofilament, desmin and smooth muscle actin. One case showed focal positivity for PDGFR-α (1/9), with no mutations found.

CONCLUSIONSGastric schwannomas share similar histologic features with conventional soft tissue schwannomas, in addition to the presence a reactive lymphoid cuff. The clinical, macroscopic, histologic and immunohistochemical features of gastric schwannomas were different from those of gastrointestinal stromal tumors and leiomyomas.

Adult ; Aged ; Aged, 80 and over ; Diagnosis, Differential ; Exons ; Female ; Follow-Up Studies ; Gastrectomy ; methods ; Gastrointestinal Stromal Tumors ; metabolism ; pathology ; Glial Fibrillary Acidic Protein ; metabolism ; Humans ; Intermediate Filament Proteins ; metabolism ; Leiomyoma ; metabolism ; pathology ; Leiomyosarcoma ; metabolism ; pathology ; Male ; Middle Aged ; Mutation ; Nerve Tissue Proteins ; metabolism ; Nestin ; Neurilemmoma ; metabolism ; pathology ; surgery ; Neurofibroma ; metabolism ; pathology ; Receptor, Platelet-Derived Growth Factor alpha ; genetics ; metabolism ; S100 Proteins ; metabolism ; Stomach Neoplasms ; metabolism ; pathology ; surgery ; Vimentin ; metabolism

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

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 study the immunophenotype and c-kit or platelet derived growth factor receptor alpha (PDGFRA) gene mutations in CD117-negative gastrointestinal stromal tumors (GISTs).

METHODSTen cases of GISTs with typical histologic features but no CD117 expression were retrieved from the archival of Department of Pathology, Peking Union Medical College Hospital, China. The cases were further evaluated for the presence of c-kit exons 9, 11, 13 and 17 mutations and PDGFRA exons 12 and 18 mutations. DNA was extracted from the paraffin-embedded tumor tissue. The PCR products were sequenced directly for the mutations. An immunohistochemical study for CD117, CD34, smooth muscle actin, desmin, S-100 protein, WT-1 and DOG-1 was also performed.

RESULTSEight of the 10 cases had the mutation tests completed. C-kit mutation in exon 9 was detected in only one case. Amongst the 10 cases studied, CD34 was expressed in 9 cases. Smooth muscle actin was focally positive in 2 cases. None of them expressed desmin or S-100 protein. DOG-1 and WT-1 were diffusely positive in 5 and 4 cases, respectively. In addition, DOG1 was diffusely but weakly positive in 1 case and focally expressed in 2 cases. Three cases were focally positive for WT-1.

CONCLUSIONPathologic diagnosis of CD117-negative GISTs can be facilitated with the application of a panel of immunohistochemical markers, including DOG-1 and WT-1.

Actins ; metabolism ; Adult ; Aged ; Anoctamin-1 ; Antigens, CD34 ; metabolism ; Chloride Channels ; Exons ; Female ; Gastrointestinal Stromal Tumors ; genetics ; metabolism ; pathology ; Humans ; Immunophenotyping ; Male ; Membrane Proteins ; metabolism ; Middle Aged ; Mutation ; Neoplasm Proteins ; metabolism ; Proto-Oncogene Proteins c-kit ; genetics ; metabolism ; Receptor, Platelet-Derived Growth Factor alpha ; genetics ; metabolism ; WT1 Proteins ; metabolism ; Young Adult

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