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F Buttitta

Publications and source records attributed to F Buttitta.

51 records · Page 3Linked to original sources
PubMed1995

mdm2 gene amplification and overexpression in non-small cell lung carcinomas with accumulation of the p53 protein in the absence of p53 gene mutations.

Fifty-three non-small cell lung carcinomas (NSCLC), previously investigated for p53 abnormalities, were studied to evaluate the status of the mdm2 gene by Southern and Northern blot analysis and expression of the mdm2 protein by immunohistochemistry with specific monoclonal antibodies. Amplification and overexpression of the mdm2 gene and nuclear accumulation of its protein product were observed in three (6%) of the NSCLC examined. All of the tumors having mdm2 abnormalities belonged to a subset of NSCLC characterized by a strong accumulation of the p53 protein in the absence of p53 gene mutations. Since mdm2 is capable of forming tight complexes with p53, possibly stabilizing it, our results suggest that this event may take place in a low percentage of NSCLC. Moreover, all of the mdm2-positive tumors were histologically classified as lung adenocarcinomas. This may indicate that the mdm2 gene is preferentially altered in this particular subtype of lung tumors.

Base Sequence↗
PubMed1995

Detection of p53 mutations by single-strand conformation polymorphisms (SSCP) gel electrophoresis. A comparative study of radioactive and nonradioactive silver-stained SSCP analysis.

p53 mutations are the most common genetic abnormality in humans tumors, but their clinical significance remains to be 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.

Carcinoma↗
PubMed1995

Int-6, a highly conserved, widely expressed gene, is mutated by mouse mammary tumor virus in mammary preneoplasia.

With a unique mouse mammary tumor model system in which mouse mammary tumor virus (MMTV) insertional mutations can be detected during progression from preneoplasia to frank malignancy, including metastasis, we have discovered a new common integration site (designated Int-6) for MMTV in mouse mammary tumors. MMTV was integrated into Int-6 in a mammary hyperplastic outgrowth line, its tumors and metastases, and two independent mammary tumors arising in unrelated mice. The Int-6 gene is ubiquitously expressed as a 1.4-kb RNA species in adult tissues and is detected beginning at day 8 of embryonic development. The nucleotide sequence of Int-6 is unrelated to any of the known genes in the GenBank database. MMTV integrates within introns of the gene in the opposite transcriptional orientation. In each tumor tested, this results in the expression of a truncated Int-6/long terminal repeat (LTR) chimeric RNA species which is terminated at a cryptic termination signal in the MMTV LTR. Since the nonrearranged Int-6 alleles in these tumors contain no mutations, we favor the conclusion that truncation of the Int-6 gene product either biologically activates its function or represents a dominant-negative mutation.

Amino Acid Sequence↗
PubMed1995

Detection of DNA mutations in acid formalin-fixed paraffin-embedded archival tumor specimens by polymerase chain reaction-single strand conformation polymorphism analysis.

A single strand conformation polymorphism analysis on polymerase chain reaction (PCR)-amplified genomic DNA was used for the detection of DNA mutations in acid formalin-fixed, paraffin-embedded tissues. Fifty non-small cell lung cancers were screened for mutations in the exon 5 of the p53 tumor suppressor gene. Structural abnormalities of the gene were found in nine (18%) of the tumors examined. The results show that paraffin-embedded tissues fixed in unbuffered formalin can be a good source of DNA for a mobility shift analysis by neutral polyacrylamide gel electrophoresis. The described procedure allows retrospective genetic studies on paraffin blocks available in all pathology departments.

Base Sequence↗
PubMed1993

p53 mutations and histological type of invasive breast carcinoma.

A polymerase chain reaction-single strand conformation polymorphism assay was used to assess p53 mutations in 148 invasive breast carcinomas, selected on the basis of their histotype. They comprised 56 lobular, 47 ductal, 19 mucinous, 18 medullary, and 8 papillary carcinomas. The distribution of p53 mutations was significantly different (P = 0.006) in the histotypes examined: mutations were frequent in medullary (39%) and ductal (26%), less common in lobular (12%), and absent in mucinous and papillary carcinomas. The frequency of mutations in the exon 5 of the p53 gene was significantly higher in medullary carcinomas than in the other histotypes: 5 (63%) of the mutations found in exon 5 were observed in medullary carcinomas (P = 0.012). One hundred twenty-two tumors from the total were also examined by immunohistochemistry for p53 overexpression using antibody PAb 1801. A specific immunostaining in neoplastic cells was present in 12 tumors. A strong correlation (P < 0.001) was observed between p53 mutations and nuclear accumulation of the p53 protein: 10 tumors were scored positive for both p53 mutation and overexpression. However, in 9 cases having a mutated p53 gene we failed to find a positive immunoreaction. A significant association (P = 0.01) was present between mutations in the p53 gene and high proliferative activity of the tumors determined by immunohistochemistry with monoclonal antibody Ki-67. Moreover, a significantly higher expression of the Ki-67 antigen was found in medullary carcinomas compared to the other histotypes. Our findings indicate that in invasive breast carcinomas structural abnormalities of the p53 gene are mainly seen in medullary and ductal tumors and that the other histological types, especially those associated with a high level of differentiation and favorable prognosis, show a very low incidence of p53 mutations.

Base Sequence↗
PubMed1993

p53 alterations in non-small cell lung cancers correlate with metastatic involvement of hilar and mediastinal lymph nodes.

Alterations of p53 are one of the most common molecular changes found in all types of lung tumors, suggesting a crucial role for p53 in bronchial carcinogenesis. However, the prognostic significance of p53 abnormalities in lung cancer patients is still unclear. By using genetic and immunohistochemical methods we have found p53 alterations in 40 of 53 (75%) primary, resected non-small cell lung cancer. A strong association (P = 0.0015) was found between deletions on chromosome region 17p13.3 and p53 mutations suggesting that loss of the wild-type p53 allele might be necessary for tumorigenesis. Correlations to clinicopathological parameters showed that p53 alterations (structural aberration of the gene and/or nuclear accumulation of the protein) are significantly linked with metastatic involvement of hilar and mediastinal lymph nodes (P < 0.01). Since the latter are well established prognostic factors for non-small cell lung cancer, p53 aberrations may also be a predictor of tumor aggressiveness.

Aged↗
PubMed1991

Host genetic background effect on the frequency of mouse mammary tumor virus-induced rearrangements of the int-1 and int-2 loci in mouse mammary tumors.

The frequency with which int-1 and int-2 are rearranged in mouse mammary tumors by mouse mammary tumor virus (MMTV)-induced insertional mutagenesis is a consequence of the host genetic background. In 75% of C3H mammary tumors, int-1 is rearranged by MMTV insertion, whereas only 30% of BALB/cfC3H tumors contain a virus-induced rearrangement of int-1. This difference is significant (P less than 0.005) and could not be accounted for by the potentially additive effect of the genetically transmitted Mtv-1-encoded virus in C3H mice. Similarly, MMTV-induced rearrangement of the int-2 gene in mammary tumors of the R111 mouse strain (59%) occurred at a significantly (P less than 0.025) higher frequency than in BALB/cfR111 (25%) mammary tumors. Moreover, in BALB/cfR111 mammary tumors, there is evidence that rearrangement of int-1 and int-2 does not occur independently (P less than 0.025). These results suggest that the long history of inbreeding for high tumor incidence of C3H and R111 mouse strains has selected for the fixation of host mutations which either complement the action of the particular int gene or affect the sensitivity of specific subpopulations of mammary epithelium to infection by particular strains of MMTV.

Animals↗
PubMedDate not supplied

p53 status is neither a predictive nor a prognostic variable in patients with advanced ovarian cancer treated with a paclitaxel-based regimen.

BACKGROUND: The aim of this study was to assess the relationship between p53 status and the clinical outcome of patients with advanced ovarian cancer treated with a paclitaxel-based regimen. PATIENTS AND METHODS: The investigation was conducted on 38 patients with FIGO stage III-IV ovarian cancer from whom tumor tissue samples for p53 protein immunostaining were obtained during initial cytoreductive surgery. All these patients subsequently received six cycles of first-line combination chemotherapy with paclitaxel 175 mg/m2 (3-hour infusion) plus carboplatin AUC 6 with or without epidoxorubicin 75 mg/m2. RESULTS: Positive p53 immunostaining was detected in tissue samples collected from 24 (63.2%) ovarian cancers. A clinical complete response was obtained in 14 (58.3%) of the 24 patients with positive p53 immunostaining compared to 9 (64.3%) of the 14 patients with negative p53 immunostaining (p = 0.717). A pathological complete response was found in 6 (25.0%) of the former compared to 4 (28.6%) of the latter (p = 0.956). Similarly, survival did not correlate with p53 status (p = 0.1271). DISCUSSION: p53 status seems to be neither a predictive nor a prognostic variable in patients with advanced ovarian cancer treated with a paclitaxel-based regimen. These results are consistent with experimental data showing that paclitaxel cytotoxicity in ovarian cancer is likely to be mediated by a p53-independent pathway.

Adult↗
PubMedDate not supplied

[Usefulness of ranitidine in the treatment of esophagitis caused by gastro-esophageal acid reflux].

The results of a randomised prospective study conducted on 40 patients with erosive oesophagitis caused by gastro-oesophageal acid reflux are reported. The patients were divided into two groups and given either ranitidine or a placebo. The clinical and endoscopic evolution confirmed by the histological findings and pH figures demonstrated a significantly better performance in the patients treated with ranitidine. No clinically significant side effects were noted.

Adult↗
PubMedDate not supplied

Preoperative serum antibodies against the p53 protein in patients with ovarian and endometrial cancer.

Antibodies against the p53 protein were measured with a sandwich-type enzyme-linked immunosorbent assay in blood samples preoperatively collected from 30 patients with ovarian cancer and 30 patients with endometrial cancer. Anti-p53 antibodies were detected in 33.3% of patients with ovarian cancer, comprising 22.2% of the 9 patients with stage I-II disease, 30.8% of the 13 patients with stage III disease, and 50.0% of the 8 patients with stage IV disease. Anti-p53 antibodies were found in none of the 4 patients with well differentiated tumors and in 38.5% of the 26 patients with moderately or poorly differentiated tumors. Among the 21 patients with stage III-IV disease, a complete clinical response to front-line platinum-based chemotherapy was obtained by 46.2% of the 13 patients without anti-p53 antibodies and 25.0% of the 8 patients with anti-p53 antibodies. Antibodies against the p53 protein were detected in only 6.7% of patients with endometrial cancer. The low incidence of anti-p53 antibodies in patients with endometrial cancer seems to suggest that the serum assay of these autoantibodies has a limited clinical relevance in the management of this malignancy. On the other hand in patients with ovarian cancer the incidence of serum anti-p53 antibodies is relatively high, and, moreover, it seems to increase with tumor stage and grade and seems to be associated with a lower response rate to chemotherapy. However, the small number of patients did not allow us to obtain statistically significant differences.

Adult↗
PubMedDate not supplied

Multidrug resistance related genes and p53 expression in human non small cell lung cancer.

BACKGROUND: Many genes (mdr1, mrp, DNA topoisomerases II) are known to be involved in the resistance to unrelated drugs (the MDR phenomenon), but the mechanisms of their activation have to be further investigated. MATERIALS AND METHODS: Because several authors showed that p53 mutated gene was able to induce mdr1 overexpression, we evaluated in 51 non small cell lung cancer samples, already tested for p53 mutations, the expression of mdr1, mrp, DNA topoisomerase II alpha and beta mRNAs by qualitative RT-PCR assays. RESULTS: Mutations of p53 were found in 56% of cases. Mdr1 expression was detected in 27%, mrp in 100%, topoisomerase alpha in 82% and beta in 94% of the samples. CONCLUSIONS: It was not possible to detect any relationship between the expression of the MDR-related genes and tumor histological type, stage or lymph node involvement. Nevertheless, a close association between p53 alterations and either mdr1 gene (p = 0.001) or DNA topoisomerase II alpha (p = 0.003) expression was found.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMedDate not supplied

Serum anti-p53 antibodies in the follow-up of patients with advanced ovarian carcinoma.

Serum anti-p53 antibodies have been detected in different human malignancies, including ovarian carcinoma. In the present investigation these autoantibodies were retrospectively measured with a new ELISA (Immunotech, Marseilles, France) before first surgery and subsequently at different times during the course of disease from 40 patients with advanced ovarian carcinoma. Anti-p53 antibodies were preoperatively found in 15 (37.5%) patients. With regard to the follow-up of these 15 patients, anti-p53 antibodies were detected in 87.8% of the 41 samples drawn when there was clinical evidence of disease compared to 57.1% of the 14 samples collected when there was no clinical evidence of tumor (p = 0.037). As for the 25 patients whose serum originally scored negative, the autoantibodies were found only in 1.8% of the 113 samples obtained during the follow-up, independently of the status of disease. In conclusion, anti-p53 antibodies are often detected in serum from patients with advanced ovarian carcinoma. However, the serial measurement of these autoantibodies does not seem to give useful clinical information for the follow-up of these patients.

Adult↗