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

No abstract available.
Adenocarcinoma* ; 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*

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

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

BACKGROUND: It is well known that oligodendrogliomas can be divided into two groups according to the 1p/19q or 1p loss of heterozygosity (LOH) status because oligodendrogliomas with the 1p/19q LOH or the 1p LOH have a better prognosis and chemosensitivity. In this study, we investigated the adequate microsatellite markers for 1p/19q LOH of oligodendroglial tumors in Korean patients. METHODS: We performed PCR that was based on the LOH test with the 1p (D1S508, D1S199, D1S2734, D1S186 & D1S312) and 19q (D19S219, D19S112, D19S412 & D19S596) microsatellite markers; these were the markers that were recommended by other researchers. We performed this PCR on microdissected paraffin embedded tissue blocks of 67 tumors from 56 cases. RESULTS: The PCR based LOH analysis revealed that 3 microsatellite markers (D1S508, D1S2734 & D1S186) of 1p and 2 markers (D19S219 & D19S412) of 19q had higher heterozygosity scores than other markers. In addition, chromosomal LOH status using these selective markers showed a statistically significant difference of prognosis for oligodendroglial tumors. CONCLUSIONS: We can suggest that the microsatellite markers with high heterozygosity scores (D1S508, D1S2734, D1S186, D19S219 and D19S412) would be adequate microsatellite markers for a PCR based LOH test of oligodendroglial tumors in Korean patients.
Humans ; Loss of Heterozygosity* ; Microsatellite Repeats* ; Oligodendroglioma ; Paraffin ; Polymerase Chain Reaction ; Prognosis

BACKGROUND: Endometrial carcinomas are pathogenetically classified into two major types; endometrioid carcinoma (EC) and serous carcinoma (SC). The most frequently altered gene in EC is the PTEN tumor suppressor gene (TSG). SC is usually associated with mutations in the p53 TSG. METHODS: To further determine the role of PTEN and p53 mutation in endometrial carcinogenesis, the analysis of 33 endometrial carcinomas, including 28 ECs and 5 SCs, for loss of heterozygosity (LOH) on 10q23 and for mutation in all 9 coding exons of PTEN and the 5-8 exons of p53, using SSCP-PCR methods was carried out. RESULTS: LOH was detected in at least one marker in 12 (54.5%) of 22 ECs, but in only one (20.0%) of 5 SCs. Somatic PTEN mutations were detected in 10 (35.7%) of 28 ECs. PTEN was altered in 67.9% of ECs and in 20.0% of SCs, including those with 10q23 LOH. No PTEN mutations were found among the SCs. Somatic p53 mutations were detected in 2 (7.1%) of 28 ECs and 3 (60.0%) of 5 SCs. CONCLUSIONS: PTEN gene alterations contribute to the pathogenesis of an endometrioid subtype of endometrial carcinoma, but not to the serous type. In contrast, p53 plays an important role in the pathogenesis of SCs.
Carcinogenesis ; Carcinoma, Endometrioid ; Clinical Coding ; Endometrial Neoplasms* ; Exons ; Female ; Genes, p53 ; Genes, Tumor Suppressor ; Loss of Heterozygosity

PURPOSE: RKIP (Raf kinase inhibitor protein) is a novel candidate tumor suppressor, known to inhibit the MAPK signaling by interfering with the MEK phosphorylation by Raf-1. The aim of this study was to investigate the expression of RKIP and analyze the pattern of inactivation and mutation of the RKIP gene in human gastric cancer. METHODS: To explore if RKIP inactivation is implicated in gastric tumorigenesis, an expression analysis on the transcription and protein expression levels and a mutational analysis of RKIP were performed in 15 human gastric cancer cell lines and 92 primary carcinoma tissues. RESULTS: Abnormal reduction of the level of RKIP expression was frequently detected in the cancer cell lines and primary tumor tissues, at both the transcript and protein levels. Moreover, the expression level of RKIP in the tumor cells was inversely correlated with the level of Erk phosphorylation, indicating that RKIP plays a key role in the regulation of the Raf-MEK-Erk signaling pathway in human gastric cells. While the expression of the RKIP transcript was not re-activated in low expressor cells by treatment with the demethylating agent 5'Aza-dC, the genomic RKIP was detected at low levels in many cancer cell lines, suggesting that an abnormal reduction of level of RKIP expression in tumors might be caused by allelic deletion of the gene rather than transcriptional silencing due to aberrant DNA hypermethylation. A loss of heterozygosity study, using an intragenic polymorphic marker, revealed that approximately 21% of the gastric cancers harbored allelic loss of the RKIP gene. CONCLUSION: Collectively, this study has demonstrated that RKIP is a tumor suppressor, whose expression is frequently downregulated by allelic deletion in human gastric cancers. This study also suggests that an altered expression of RKIP might contribute to the development of gastric cancer via abnormal elevation of the Raf-Erk signaling pathway.
Carcinogenesis ; Cell Line ; DNA ; Humans* ; Loss of Heterozygosity ; Phosphorylation ; Phosphotransferases* ; Stomach Neoplasms*