No abstract available.
Adenocarcinoma* ; Loss of Heterozygosity*

No abstract available.
Colorectal Neoplasms* ; Loss of Heterozygosity*

BACKGROUND/AIMS: The status of tumor suppression gene can be assessed indirectly by analyzing the loss of heterozygosity. Hepatoblastoma is a malignant liver tumor in childhood. To find the molecular carcinogenetic mechanism of hepatoblastoma, loss of heterozygosity (LOH) of p73, APC and p53 was studied. MATERIALS AND METHODS: Hepatoblastoma tissues from thirty-three cases were collected by lobectomy or tumorectomy. On H- stained sections, normal and tumor cells were microdissected separately and LOH analysis was perfomed using 8 markers: six of p73, one of APC and one of p53. RESULTS: Number of cases showing at least one LOH in six p73 markers was four out of twenty- six (15.4%): each LOH frequencies in D1S160, D1S170, D1S199, D1S228, D1S243 and D1S253 were in order of 7.7%, 0%, 9.1%, 0%, 12.5% and 0%. LOH frequency of APC was 41.7% and that of p53 was 13.3%. CONCLUSION: Low LOH frequency of p73 related markers indicates that p73 gene may not be implicated in carcinogenesis of hepatoblastoma.
Carcinogenesis ; Hepatoblastoma* ; Liver ; Loss of Heterozygosity*

No abstract available.
Genetic Loci* ; Loss of Heterozygosity* ; Stomach Neoplasms*

OBJECTIVE: Allelic losses or loss of heterozygosity (LOH) at many chromosomal loci have been found in the cells of meningiomas. The objective of this study was to evaluate LOH at several loci of different chromosomes (1p32, 17p13, 7q21, 7q31, and 22q13) in different grades of meningiomas. METHODS: Forty surgical specimens were obtained and classified as benign, atypical, and anaplastic meningiomas. After DNA extraction, ten polymorphic microsatellite markers were used to detect LOH. Medical and surgical records, as well as pathologic findings, were reviewed retrospectively. RESULTS: LOH at 1p32 was detected in 24%, 60%, and 60% in benign, atypical, and anaplastic meningiomas, respectively. Whereas LOH at 7q21 was found in only one atypical meningioma. LOH at 7q31 was found in one benign meningioma and one atypical meningioma. LOH at 17p13 was detected in 4%, 40%, and 80% in benign, atypical, and anaplastic meningiomas, respectively. LOH at 22q13 was seen in 48%, 60%, and 60% in benign, atypical, and anaplastic meningiomas, respectively. LOH results at 1p32 and 17p13 showed statistically significant differences between benign and non-benign meningiomas. CONCLUSION: LOH at 1p32 and 17p13 showed a strong correlation with tumor progression. On the other hand, LOH at 7q21 and 7q31 may not contribute to the development of the meningiomas.
DNA ; Hand ; Loss of Heterozygosity ; Meningioma ; Microsatellite Repeats ; Retrospective Studies

PURPOSE: Genomic alterations and abnormal expression of the fragile histidine triad (FHIT) gene in gastric cancer were examined to determine whether the FHIT gene is actually a frequent target for alteration during gastric carcinogenesis. MATENRIALS AND METHODS: To correlate DNA and RNA lesions of the FHIT gene with the effect on FHIT protein expression, in 40 gastric cancers, we investigated the FHIT gene for loss of heterozygisity (LOH), aberrant transcripts, and protein expression. RESULTS: Allelic loss at D3S1300 was detected in 7 of 38 (19%) informative cases. Aberrant transcripts were observed in 20 of 40 (50%) cases. Significant reduction of FHIT protein expression was observed in 22 of 40 (55%) cases. Aberrant FHIT transcription was shown to be associated with loss of FHIT protein expression. However, aberrent FHIT transcripts themselves were not associated with any clinicopathological parameters, such as age, sex, tumor site, or clinical stage. Moreover, there was no association between the presence of LOH at D3S1300 and the expression of aberrant FHIT transcripts. CONCLUSION: The high frequency of aberrant FHIT transcripts, the significant rate of LOH at D3S1300, and the altered expression of the FHIT protein indicate that alterations of the FHIT gene can play an important role in gastric carcinogenesis.
Carcinogenesis ; DNA ; Gene Expression* ; Histidine* ; Loss of Heterozygosity ; RNA ; Stomach Neoplasms*

The objectives of this study were to characterize the alterations of 3p and 9p in sporadic renal cell carcinomas (RCC) and to assess the relationship between the clinical stages or tumor size and the alteration of these chromosomes. Thirty eight archival, paraffin embedded tissue sections from 38 patients with RCC were analyzed for loss of heterozygosity (LOH) at 3p and 9p with 11 microsatellite markers. LOH was detected in 81.6% (31/38) and 37.8% (14/37) at 3p and 9p, respectively. The frequencies of LOH at VHL and FHIT locus were 75.6% and 72.2%, respectively. Twelve cases out of 38 showed LOH at both 9p21 and 3p. The loss of 3p in the samples tested was not related to clinical stages and tumor size, but that of 9p21 was significantly associated with advanced stage and larger tumor size. These results support that 3p deletion, including VHL and FHIT gene, play a critical role in the tumorigenesis of sporadic RCC, especially at early stage, and that 9p21 may contribute to the progression of sporadic RCC.
Carcinogenesis ; Carcinoma, Renal Cell* ; Humans ; Loss of Heterozygosity* ; Microsatellite Repeats ; Paraffin

Loss of heterozygosity (LOH) has been established as an important genetic mechanism giving rise to malignant neoplasia. The mechanism of LOH has been shown to cause basal cell carcinoma and malignant melanoma as well as other types of skin cancer. A few studies on LOH in sporadic keratoacanthomas have been reported. The purpose of this study was to investigate the significance of LOH in the pathogenesis of sporadic keratoacanthomas developed in 10 Korean patients. The presents of LOH at 7 microsatellite markers (D2S286, D3S1317, D5S346, D9S160, D9S171, D10S185, and D17S261) were evaluated in sporadic keratoacanthomas. LOH was found in only 1 of 10 cases at D10S185. The low frequency of LOH detected in this study suggests that LOH may not be significant in the induction of sporadic keratoacanthomas.
Adult ; Aged ; Female ; Humans ; Keratoacanthoma/*genetics ; *Loss of Heterozygosity ; Male ; Middle Aged ; Research Support, Non-U.S. Gov't

BACKGROUND: Loss of heterozygosity (LOH) and mutation of the p16 tumor suppressor gene have been detected in non-Hodgkin's lymphomas (NHLs). Recently, hypermethylation of the p16 gene has been reported. The role of p16 gene alterations in the genesis of NHLs and their high-grade transformations require explanation. METHODS: LOH of D9S171 and IFNA microsatellite markers, DNA hypermethylation, and mutation of exon 1 and 2A were assessed in 43 cases of NHLs. The genetic abnormalities were compared with the protein expression by immunohistochemistry, and they were evaluated according to the histologic subtypes, grades and immunophenotypes. RESULTS: DNA hypermethylation was the most common p16 gene abnormality and was found in 30 of 39 cases (76.9%). Eight cases (18.6%) showed LOH in one or both microsatellite markers, and five cases (11.6%) showed mutations in exon 1 or 2A. Loss of protein expression was seen in 17 cases (39.5%) and was associated with mutation and LOH. Loss of protein was more frequent in high-grade lymphomas than in low-grade lymphomas. CONCLUSION: These results suggest that the functional loss of the p16 gene contributes to the development of NHLs, especially to the development of high-grade lymphomas.
DNA ; Exons ; Genes, p16* ; Genes, Tumor Suppressor ; Immunohistochemistry ; Loss of Heterozygosity ; Lymphoma ; Lymphoma, Non-Hodgkin* ; Microsatellite Repeats

PURPOSE: Individual gastric cancers demonstrate complicated genetic alterations. The PCR-based analysis of polymorphic microsatellite sequences on cancer-related chromosomes has been used to detect chromosomal loss and microsatellite instability. For the purpose of preoperative usage, we analyzed the correspondance rate of the microsatellite genotype between endoscopic biopsy and surgical specimens. MATERIALS AND METHODS: Seventy-three pairs of biopsy and surgical specimens were examined for loss of heterozygosity and microsatellite instability by using 40 microsatellite markers on eight chromosomes. Microsatellite alterations in tumor DNAs were classified into a high-risk group (baseline- level loss of heterozygosity: 1 chromosomal loss in diffuse type and high-level loss of heterozygosity: 4 or more chromosomal losses) and a low-risk group (microsatellite instability and low-level loss of heterozygosity: 2 or 3 chromosomal losses in diffuse type or 1~3 chromosomal losses in intestinal type) based on the extent of chromosomal loss and microsatellite instability. RESULTS: The chromosomal losses of the biopsy and the surgical specimens were found to be different in 21 of the 73 cases, 19 cases of which were categorized into a genotype group of similar extent. In 100 surgical specimens, the high-risk genotype group showed a high incidence of nodal involvement (19 of 23 cases: < or =5 cm; 23 of 24 cases: >5 cm) irrespective of tumor size while the incidence of nodal involvement for the low-risk genotype group depended on tumor size (5 of 26 cases: < or =5 cm; 18 of 27 cases: >5 cm). Extraserosal invasion was more frequent in large-sized tumor in both the high-risk genotype group (< or =5 cm: 12 of 23 cases; >5 cm: 23 of 24 cases) and the low-risk genotype group (< or =5 cm: 7 of 26 cases; >5 cm: 16 of 27 cases). The preoperative prediction of tumor invasion and nodal involvement based on tumor size and genotype corresponded closely to the pathologic tumor stage (ROC area>0.7). CONCLUSION: An endoscopic biopsy specimen of gastric cancer can be used to make a preoperative genetic diagnosis that accurately reflect the genotype of the corresponding surgical specimen.
Biopsy* ; Classification* ; Diagnosis ; DNA ; Genotype ; Incidence ; Loss of Heterozygosity ; Microsatellite Instability ; Microsatellite Repeats* ; Stomach Neoplasms*