ISSN:1052-9551    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:1052-9551    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Twenty-nine samples from 28 cases of vulvar squamous cell carcinoma, of which 13 fulfilled the criteria of the bowenoid subtype (mean age 45 years, range 31–68) and 16 of the usual subtype of invasive squamous cell carcinoma (ISCC) (mean age 67.5 years, range 34–83) were investigated for human papillomavirus (HPV) DNA, TP53 alterations, andmdm2andbcl-2gene product deregulation. Microscopically all the bowenoid subtype cases (group I) showed a high-grade intraepithelial (VIN 3, carcinoma in situ) lesion associated with early invasive carcinoma in six cases and overt invasive carcinoma in one. By contrast, no evidence of early carcinoma was present in the ISCCs (group II). By in situ hybridization and/or Southern blot hybridization or polymerase chain reaction (PCR), HPV-DNA was detected in all cases of group I and in four of 16 cases (25%) of group II, two only by Southern blot after PCR. By single-strand conformation polymorphism and immunocytochemistry only wild-type TP53 and absence of detectable p53 product, respectively, were found in all cases of group I, i.e., in high-risk HPV-positive carcinomas, whereas mutations and/or p53 overexpression accounted for 75% in group II, i.e., in mainly HPV-negative carcinomas. The TP53 gene mutations observed in invasive carcinomas were significantly related to node-positive cases (p = 0.04). Taken together and in agreement with in vitro data, these results support the view that an alteration of TP53, gained either by interaction with viral oncoproteins or by somatic mutations, is a crucial event in the pathogenesis of vulvar carcinomas, but that TP53 mutations are mainly associated with disease progression. Finally, a preliminary immunocytochemical analysis seems to speak against the possible involvement of both MDM2 and BCL-2 gene products in the development of vulvar carcinoma.

ISSN:1052-9551    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

p53 mutations are the most common genetic abnormality in human tumors, but their clinical significance remains to he precisely elucidated. Conventional single-strand conformation polymorphism (SSCP) analysis, a well-established technique for detecting p53 mutations, uses radioactively labeled polymerase chain reaction (PCR) products, which migrate abnormally in the presence of mutations. We performed radioactive PCR-SSCP analysis in a series of 30 formalin-fixed, paraffin-embedded ovarian carcinomas and two cell lines (SW480 and Caov4) harboring known homozygous p53 mutations and compared the results with nonradioactive silver-stained SSCP. The purpose was to assess whether nonradioactive SSCP is suitable for detecting p53 mutations in a rapid, sensitive, cost-effective fashion, without the need of radioactive isotopes. We accomplished PCR amplification of p53 exons 5 through 8 in 26 carcinomas, and radioactive SSCP detected p53 mutations in 13 tumors: three mutations were localized in exon 5, six in exon 6, two in exon 7, and two in exon 8. All mutations were correctly identified with nonradioactive SSCP, except for one exon 8 mutation. To establish the sensitivity of nonradioactive SSCP, DNA samples of SW480 and Caov4 were mixed with increasing amounts (0–90%) of normal DNA and subjected to PCR-SSCP analysis. Mutations were detected until the concentration of SW480 and Caov4 was 15% and 10% respectively, of the total sample. The results of our investigation demonstrate that nonradioactive silver-stained SSCP is a sensitive, rapid, and simple technique to detect p53 mutations, even in formalin-fixed tissues, and could be easily used to investigate large series of patients to assess the clinical significance of p53 mutations in human tumors.

ISSN:1052-9551    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Alterations of p53 suppressor gene as a possible indicator of the metastatic potential of thyroid carcinomas were evaluated in a cohort of 45 thyroid carcinomas. Well-differentiated papillary and follicular carcinomas were evaluated; the poorly differentiated and the undifferentiated forms were excluded from the studies. Tumors were divided into two groups: those giving no metastasis for >10 years and those developing metastasis within 5 years. Gene alterations were tested by immunocytochemical detection of p53 gene expression and by determining loss of heterozygosity (LOH). Considering the two methods together, p53 damages were observed in two out of 11 papillary carcinomas without metastasis (18.1%), one out of nine papillary carcinomas with metastasis (11.1%), two out of 14 follicular carcinomas without metastasis (14.2%), and five out of 11 follicular carcinomas with metastasis (45.4%). Statistical χ2test showed significantly (p = 0.05) only between follicular carcinomas with and without metastasis thus p53 damage may have an impact for metastatic potential of follicular thyroid carcinomas.

ISSN:1052-9551    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Mutations to the K-rasoncogene and p53 tumor suppressor gene are two of the most common genetic lesions in human cancers. In the present study we examined the clonality of colorectal tumors with respect to each of these genetic alterations. Screening for mutations was carried out using the polymerase chain reaction—based technique of single-strand conformation polymorphism. Eleven primary colorectal adenocarcinomas and two secondary adenocarcinomas were analyzed at four different sites within the tumor. Involved pericolic lymph nodes were collected from nine of these cases, a metastatic deposit in the liver was obtained in one case, and adjacent adenomatous lesions were collected in two cases. Seven tumors contained mutations in either the K-rasor p53 genes. In all cases, DNA derived from multiple sites within an individual tumor or metastatic deposits arising from that tumor showed the same pattern of gene mutation. Immunohistochemical staining for p53 protein over-expression also showed similar patterns of reactivity within individual tumors and their metastatic deposits. These results suggest that the major clonal expansion of colorectal carcinomas occurs after the acquisition of mutations in these genes. Our results also indicate that sampling errors are unlikely to occur in molecular studies aimed at defining the role of these genes in colorectal cancer progression.

ISSN:1052-9551    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

The p53 tumor suppressor gene has been found to be altered in almost all human solid tumors, whereas K-rasgene mutations have been observed in a limited number of human cancers (adenocarcinoma of colon, pancreas, and lung). Studies of mutational inactivation for both genes in the same patient's sample on non-small-cell lung cancer have been limited. In an effort to perform such an analysis, we developed and compared methods (for the mutational detection of p53 and K-rasgene) that represent a modified and universal protocol, in terms of DNA extraction, polymerase chain reaction (PCR) amplification, and nonradioisotopic PCR-single-strand conformation polymorphism (PCR-SSCP) analysis, which is readily applicable to either formalin-fixed, paraffin-embedded tissues or frozen tumor specimens. We applied this method to the evaluation of p53 (exons 5–8) and K-ras(codon 12 and 13) gene mutations in 55 cases of non-small-cell lung cancer. The mutational status in the p53 gene was evaluated by radioisotopic PCR-SSCP and compared with PCR-SSCP utilizing our standardized non-radioisotopic detection system using a single 6-μm tissue section. The mutational patterns observed by PCR-SSCP were subsequently confirmed by PCR-DNA sequencing. The mutational status in the K-rasgene was similarly evaluated by PCR-SSCP, and the specific mutation was confirmed by Southern slot-blot hybridization using32P-labeled sequence-specific oligonucleotide probes for codons 12 and 13. Mutational changes in K-ras(codon 12) were found in 10 of 55 (18%) of non-small-cell lung cancers. Whereas adenocarcinoma showed K-rasmutation in 33% of the cases at codon 12, only one mutation was found at codon 13. As expected, squamous cell carcinoma samples (25 cases) did not show K-rasmutations. Mutations at exons 5–8 of the p53 gene were documented in 19 of 55 (34.5%) cases. Ten of the 19 mutations were single nucleotide point mutations, leading to amino acid substitution. Six showed insertional mutation, and three showed deletion mutations. Only three samples showed mutations of both K-rasand p53 genes. We conclude that although K-rasand p53 gene mutations are frequent in non-small-cell lung cancer, mutations of both genes in the same patient's samples are not common. We also conclude that this universal nonradioisotopic method is superior to other similar methods and is readily applicable to the rapid screening of large numbers of formalin-fixed, paraffin-embedded or frozen samples for the mutational analysis of multiple genes.

ISSN:1052-9551    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

The proximal portion of human chromosome 22q has been implicated in the pathogenesis of a clinically diverse group of conditions including DiGeorge sequence (DGS), velocardiofacial syndrome, and CHARGE association as well as isolated conotruncal heart anomalies. Frequently, overlap in the clinical presentation of these syndromes occurs and, recently, the presence of microdeletions on chromosome 22q11.2 with varying frequencies has been demonstrated in these syndromes. Using fluorescence in situ hybridization (FISH), we assessed 20 consecutive patients who were cytogenetically and clinically evaluated for a suspected syndrome that could be due to a microdeletion of chromosome 22q11.2. After cytogenetic testing and full clinical evaluation, we compared the results by FISH with the final clinical diagnosis and karyotype results. We found that microdeletions of 22q11.2 were detected in three of the five patients who were evaluated for DGS. The three cases with microdeletions appeared clinically to have DGS while the two negative cases were more atypical. High-resolution banding techniques did not detect a microdeletion in any of the cases; however, one of the 20 patients had a translocation between chromosomes 13 and 22. This patient also had a microdeletion of 22q11.2 detected by FISH and clinical features of DGS. None of the patients who were evaluated for disorders related to DGS showed microdeletions. We conclude that FISH is a useful, easily applied technique for the diagnosis of 22q11.2 microdeletion syndromes, particularly DGS. This test may also be useful in genetic counseling and in both prenatal and postnatal diagnoses.

ISSN:1052-9551    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

We studied the expression of insulin-like growth factor II (IGF2) and Wilms' tumor gene (WTI) in nine cases of congenital mesoblastic nephroma (CMN) and five cases of first trimester fetal kidneys by in situ hybridization. Our aim was to determine their site of expression and to correlate their histogenetic relationship to those of other childhood renal tumors. Our results showed that all nine cases of CMN (classic, mixed, and cellular) contained abundant IGF2 but not WT1 transcripts. The IGF2 transcripts were diffusely distributed over the tumor cells. These findings suggest that CMN is derived from primitive mesenchymal nephrogenic cells and have a potential to differentiate into a stromal cell lineage.

ISSN:1052-9551    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

During standard registration of incoming surgery specimens, loss of registration numbers may occur. In our laboratory two series of small bladder biopsies (numbered I–V and I–VI, respectively), obtained from two patients, were given the same laboratory registration number. The biopsies were of similar size and embedded in paraffin. Thus, five pairs of Roman-numbered paraffin blocks had the same laboratory registration numbers. The histological findings in several biopsies were similar, some showing carcinoma in situ. Only from biopsy number VI was the identity retained, and this specimen could be used as a reference. We used polymerase chain reaction (PCR)-driven microsatellite marker analysis to identify the specimens using five different microsatellite markers. Within 48 h, two different banding patterns were revealed, allowing us to distinguish the two series. In addition, in one biopsy which showed carcinoma in situ of the bladder, microsatellite instability was observed while in none of this patient's other biopsies containing carcinoma in situ could this phenomenon be detected, which may indicate intratumor heterogeneity or multifocality. In conclusion, it is possible to solve the problem of mixing up small paraffin-embedded biopsies by using microsatellite marker PCR.

ISSN:1052-9551    

出版商:OVID    

年代:1995

数据来源: OVID