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Biomedical subjects

T Peretz

Publications and source records attributed to T Peretz.

At least 19 recordsLinked to original sources
PubMed2006

Multimarker RT-PCR assay for the detection of minimal residual disease in sentinel lymph nodes of breast cancer patients.

The presence of metastases in lymph nodes is the most powerful prognostic factor in breast cancer patients. Routine histological examination of lymph nodes has limited sensitivity for the detection of breast cancer metastases. The aim of the present study was to develop a multimarker reverse transcriptase-polymerase chain reaction (RT-PCR) assay for the detection of minimal residual disease in sentinel nodes of breast cancer patients. RNA was extracted from 30 sentinel lymph nodes (SLN) obtained from 28 patients, three primary breast cancers (positive controls), three lymph nodes from patients with benign diseases, and peripheral blood lymphocytes of 10 healthy volunteers (negative controls). RT-PCR was performed using the following markers; cytokeratin (CK)-19, NY-BR-1 and mammaglobin B. RT-PCR results were compared to enhanced histopathologic examination and immunohistochemistry (IHC). All three positive controls showed strong PCR amplification for all three markers. None of the 13 negative controls was amplified by any of the three markers. Among the 30 SLN analysed, breast cancer metastases were detected in six SLNs by routine histology, in eight by IHC and in 15 by RT-PCR. We conclude that a multimarker RT-PCR assay probing for NY-BR-1, mammaglobin-B, and CK-19 is more sensitive compared to enhanced pathologic examination. This method may prove to be of value in breast cancer staging and prognosis evaluation.

Adenocarcinoma↗
PubMed2006

Tumor suppressor p53 regulates heparanase gene expression.

Mammalian heparanase degrades heparan sulfate, the most prominent polysaccharide of the extracellular matrix. Causal involvement of heparanase in tumor progression is well documented. Little is known, however, about mechanisms that regulate heparanase gene expression. Mutational inactivation of tumor suppressor p53 is the most frequent genetic alteration in human tumors. p53 is a transcription factor that regulates a wide variety of cellular promoters. In this study, we demonstrate that wild-type (wt) p53 binds to heparanase promoter and inhibits its activity, whereas mutant p53 variants failed to exert an inhibitory effect. Moreover, p53-H175R mutant even activated heparanase promoter activity. Elimination or inhibition of p53 in several cell types resulted in a significant increase in heparanase gene expression and enzymatic activity. Trichostatin A abolished the inhibitory effect of wt p53, suggesting the involvement of histone deacetylation in negative regulation of the heparanase promoter. Altogether, our results indicate that the heparanase gene is regulated by p53 under normal conditions, while mutational inactivation of p53 during cancer development leads to induction of heparanase expression, providing a possible explanation for the frequent increase of heparanase levels observed in the course of tumorigenesis.

Animals↗
PubMed2004

A single-nucleotide polymorphism in the RAD51 gene modifies breast cancer risk in BRCA2 carriers, but not in BRCA1 carriers or noncarriers.

Variation in the penetrance estimates for BRCA1 and BRCA2 mutation carriers suggests that other genetic polymorphisms may modify the cancer risk in carriers. The RAD51 gene, which participates in homologous recombination double-strand breaks (DSB) repair in the same pathway as the BRCA1 and BRCA2 gene products, is a candidate for such an effect. A single-nucleotide polymorphism (SNP), RAD51-135g-->c, in the 5' untranslated region of the gene has been found to elevate breast cancer (BC) risk among BRCA2 carriers. We genotyped 309 BRCA1/2 mutation carriers, of which 280 were of Ashkenazi origin, 166 noncarrier BC patients and 152 women unaffected with BC (a control group), for the RAD51-135g-->c SNP. Risk analyses were conducted using COX proportional hazard models for the BRCA1/2 carriers and simple logistic regression analysis for the noncarrier case-control population. BRCA2 carriers were also studied using logistic regression and Kaplan-Meier survival analyses. The estimated BC hazard ratio (HR) for RAD51-135c carriers adjusted for origin (Ashkenazi vs non-Ashkenazi) was 1.28 (95% CI 0.85-1.90, P=0.23) for BRCA1/2 carriers, and 2.09 (95% CI 1.04-4.18, P=0.04) when the analysis was restricted to BRCA2 carriers. The median BC age was younger in BCRA2-RAD51-135c carriers (45 (95% CI 36-54) vs 52 years (95% CI 48-56), P=0.05). In a logistic regression analysis, the odds ratio (OR) was 5.49 (95% CI 0.5-58.8, P=0.163). In noncarrier BC cases, carrying RAD51-135c was not associated with BC risk (0.97; 95% CI 0.47-2.00). These results indicate significantly elevated risk for BC in carriers of BRCA2 mutations who also carry a RAD51-135c allele. In BRCA1 carriers and noncarriers, no effect for this SNP was found.

Adult↗
PubMed2004

Interleukin-2 improves tumour response to DNP-modified autologous vaccine for the treatment of metastatic malignant melanoma.

This paper is a report of response rate (RR) and survival of 34 metastatic melanoma patients who received a dinitrophenyl (DNP)-modified autologous melanoma cell vaccine. In all, 27 patients started the vaccine as a primary treatment for metastatic melanoma and seven started it as an adjuvant, with no evidence of disease at the time, but had developed new metastases. Interleukin-2 (IL-2) was administered in 24 out of the 34 patients: 19 who progressed on vaccine alone and five who had the combination from start. Interleukin-2 was administered in the intravenous, bolus high-dose regimen (seven patients) or as subcutaneous (s.c.) low-dose treatment (17). Overall response for the entire group was 35% (12 patients out of 34), 12% having a complete response (CR) and 23% a partial response (PR). However, only two patients had tumour responses while on the vaccine alone, whereas the other 10 demonstrated objective tumour regression following the combination with IL-2 (two CR, eight PR), lasting for a median duration of 6 months (range 3-50 months). Of the 12 responding patients, 11 attained strong skin reactivity to the s.c. injection of irradiated, unmodified autologous melanoma cells. None of the patients with a negative reactivity experienced any tumour response. Patients with positive skin reactions survived longer (median survival - 54 months). The results suggest enhanced RRs to the combination of IL-2 and autologous melanoma vaccine. Skin reactivity to unmodified autologous melanoma cells may be a predictor of response and improved survival, and therefore a criterion for further pursuing of immunotherapeutic strategies.

Adjuvants, Immunologic↗
PubMed2004

Use of tranquilizers and sleeping pills among cancer patients is associated with a poorer quality of life.

PURPOSE: To evaluate the association between sleeping pill/tranquilizer (SP/T) use and quality of life (QOL) among cancer patients. PATIENTS AND METHODS: Oncology patients (n = 909) in three Israeli hospitals were interviewed in clinics, day centers and in-patient departments regarding SP/T use in the previous week. Crude and adjusted QOL scores, measured using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-C30 (EORTC QLQ-C30), were compared in users vs. non-users. RESULTS: Sleeping pill/tranquilizer use was self-reported by 234 (25.7%) participants, but rarely documented in medical charts. Factors associated with SP/T use were female gender (adjusted Odds ratio, OR: 1.79; 95% Confidence interval, CI: 1.22-2.62, age (OR: 4.6; 95% CI: 1.66-12.53 for age 70+), place of birth (OR: 1.97; 95% CI: 1.19-3.26 for Eastern Europe compared with Israel), concomitant use of painkillers (OR: 2.88; 95% CI: 1.97-4.20) and presence of cardiovascular disease (OR: 2.41; 95% CI: 1.48-3.91). Controlling these factors as well as disease status, users had a poorer QOL on all functional scales (p < 0.001) as well as global QOL. Furthermore, users reported increased severity of symptoms, especially fatigue, insomnia, pain, dyspnea and constipation (p < 0.01), compared to non-users. CONCLUSIONS: Use of SP/T, reported by one fourth of cancer patients, was associated with substantially poorer QOL and increased severity of symptoms. Causal inference is not possible given the cross-sectional design. Periodic inquiry regarding use of these medications in the Oncology Clinic is recommended since it may identify patients with poor QOL and unmet needs.

Adolescent↗
PubMed2004

Production and purification of melanoma gp100 antigen and polyclonal antibodies.

gp100 is a melanoma-associated antigen found to carry immunogenic epitopes that can induce a CTL response against tumor cells. Production and purification of large quantities of this polypeptide may be important in the context of diagnosis and vaccinating against melanoma. To overcome the hydrophobic nature of gp100, we cloned and expressed only a part of the protein, and obtained a hydrophilic recombinant polypeptide (HR-gp100) that contained most of the immunogenic peptides. High yield was achieved in an Escherichia coli expression system. The protein was purified by AKTA Prime using anionic-columns. Polyclonal antibodies developed in chicken against HR-gp100 were efficient at detecting gp100 in melanoma cells, as determined by Western blot analysis and by immunohistochemistry. HR-gp100 can be used to develop a vaccine against melanoma. Antibodies to HR-gp100 may be used to detect tumors of melanocytic origin or to determine the level of gp100 expression in tumors prior to immunotherapy with the protein or one of its peptides.

Amino Acid Sequence↗
PubMed2004

Targeting pulmonary metastases of renal cell carcinoma by inhalation of interleukin-2.

INTRODUCTION: Pulmonary metastases of renal cell carcinoma (RCC) are associated with poor prognosis. Inhalation therapy with interleukin-2 (IL-2) is thus an appealing method for palliation. This multicenter study summarizes the national experience of IL-2 inhalation in patients with lung metastases of RCC. PATIENTS AND METHODS: Forty patients (median, 66.5 years of age) with radiologically documented progressing pulmonary metastases were enrolled. All patients had to be able to comply with inhalation technique, and were not candidates for other treatment options. Twenty-eight patients were systemic treatment-naïve. The protocol included three daily inhalations of IL-2 to a total dose of 18 MU. Treatment had to be continued until one of the following occurred: progression; a complete response; a life threatening toxicity; or patient refusal. Response was assessed using the Response Evaluation Criteria in Solid Tumors (RECIST) system. RESULTS: The disease-control rate reached 57.5%, with a partial response rate of 2.5% and a disease stabilization rate of 55%. Median time to progression was 8.7 months. The main side-effects were cough and weakness. CONCLUSIONS: Inhalation of IL-2 for the treatment of pulmonary metastases in RCC is feasible, tolerable and beneficial in controlling progressive disease for considerable periods of time. The definition of response of biological therapy may need to be re-assessed and modified: stable disease should be regarded as a favorable response.

Administration, Inhalation↗
PubMed2003

Population attributes affecting the prevalence of BRCA mutation carriers in epithelial ovarian cancer cases in israel.

OBJECTIVE: The objective was to evaluate the prevalence of BRCA1/2 mutations in selected categories of ovarian cancer patients in Israel. METHODS: Blood samples and specimens of ovarian tumors were obtained in the course of a national case control study of women with ovarian cancer in Israel. Eight hundred ninety-six patients with epithelial ovarian cancer, 40 cases with nonepithelial ovarian cancer, and 68 with primary peritoneal cancer were tested for the BRCA mutations. Analysis of the three common BRCA mutations in Israel (185delAG, 5382insC in BRCA1, and 6174delT in BRCA2) was done using a multiplex polymerase chain reaction assay. A multivariate logistic regression model was used to assess the association of mutation carrier status and other factors (age, origin, family history, and clinical variables). RESULTS: Of the 779 invasive epithelial ovarian cancer cases, 29.4% were mutation carriers. The prevalence of the mutations was higher among women below age 60 and in more advanced cases. The prevalence was low in mucinous tumors. There was almost a twofold excess of mutations among women with positive family history (45.7%), but still 26.5% of the family history negative cases were carriers. As expected, we found a higher rate of mutation carriers among the Ashkenazi group (34.2%) and 55% among Ashkenazi women with positive family history. No subjects born in North Africa were mutation positive. CONCLUSION: BRCA mutations are strongly associated with ovarian cancer and they are present in variable rates in distinct age, ethnic, and histopathologic categories.

Epithelial Cells↗
PubMed2002

Autologous cell vaccine as a post operative adjuvant treatment for high-risk melanoma patients (AJCC stages III and IV). The new American Joint Committee on Cancer.

This study evaluates the overall survival and disease free survival of melanoma patients that were treated with an autologous melanoma cell vaccine, administered as a post-operative adjuvant. Included are 43 patients with totally resected metastatic melanoma (28-AJCC stage III, 15-AJCC stage IV), with a median follow up of 34 months (6-62). The treatment consisted of eight doses of a vaccine made of 10-25x10(6) autologous melanoma cells either released from the surgical specimen or grown in cell cultures. Tumour cells were conjugated with hapten dinitrophenyl, mixed with Bacille Calmette Guérin and irradiated to 110 Gy. Both disease free survival and overall survival were found to be correlated with intensity of evolving delayed type hypersensitivity to subcutaneous injection of unmodified melanoma cells. Patients with a delayed type hypersensitivity reaction of > or =10 mm had a median disease free survival of 17 months (mean 35 months) and a mean overall survival of 63 months (median not reached). In contrast, patients with a negative or weak delayed type hypersensitivity had a median disease free survival of 9 months (relative risk of recurrence=4.5, P=0.001), and a median overall survival of 16 months (relative risk of death=15, P=0.001). Stage III patients with a positive delayed type hypersensitivity reaction had an improved disease free survival of 16 months and a mean overall survival of 38 months, whereas patients with a negative delayed type hypersensitivity had a median disease free survival of 7 months (relative risk=4.5, P=0.02) and a median overall survival of 16 months (relative risk=9.5, P=0.005). The adjuvant administration of autologous melanoma vaccine was associated with improved disease-free and overall survival to selected patients who successfully attained anti-melanoma reactivity as detected by positive delayed type hypersensitivity reactions to unmodified melanoma cells.

Cancer Vaccines↗
PubMed2001

CAG and GGC repeat polymorphisms in the androgen receptor gene and breast cancer susceptibility in BRCA1/2 carriers and non-carriers.

Variation in the penetrance estimates for BRCA1 and BRCA2 mutations carriers suggests that other genetic polymorphisms may modify the cancer risk in carriers. A previous study has suggested that BRCA1 carriers with longer lengths of the CAG repeat in the androgen receptor (AR) gene are at increased risk of breast cancer (BC). We genotyped 188 BRCA1/2 carriers (122 affected and 66 unaffected with breast cancer), 158 of them of Ashkenazi origin, 166 BC cases without BRCA1/2 mutations and 156 Ashkenazi control individuals aged over 56 for the AR CAG and GGC repeats. In carriers, risk analyses were conducted using a variant of the log-rank test, assuming two sets of risk estimates in carriers: penetrance estimates based on the Breast Cancer Linkage Consortium (BCLC) studies of multiple case families, and lower estimates as suggested by population-based studies. We found no association of the CAG and GGC repeats with BC risk in either BRCA1/2 carriers or in the general population. Assuming BRCA1/2 penetrance estimates appropriate to the Ashkenazi population, the estimated RR per repeat adjusted for ethnic group (Ashkenazi and non-Ashkenazi) was 1.05 (95%CI 0.97-1.17) for BC and 1.00 (95%CI 0.83-1.20) for ovarian cancer (OC) for CAG repeats and 0.96 (95%CI 0.80-1.15) and 0.90 (95%CI 0.60-1.22) respectively for GGC repeats. The corresponding RR estimates for the unselected case-control series were 1.00 (95%CI 0.91-1.10) for the CAG and 1.05 (95%CI 0.90-1.22) for the GGC repeats. The estimated relative risk of BC in carriers associated with > or =28 CAG repeats was 1.08 (95%CI 0.45-2.61). Furthermore, no significant association was found if attention was restricted to the Ashkenazi carriers, or only to BRCA1 or BRCA2 carriers. We conclude that, in contrast to previous observations, if there is any effect of the AR repeat length on BRCA1 penetrance, it is likely to be weak.

Adult↗
PubMed2001

Determinants of the use of complementary therapies by patients with cancer.

PURPOSE: We performed a survey of Israeli oncology patients to examine the extent of their use of complementary therapies (CT) and to compare sociodemographic, psychologic, and medical characteristics, attitudes, and quality of life of users and nonusers of CT. PATIENTS AND METHODS: Questionnaires were administered to 1,027 patients attending ambulatory and inpatient hematology or oncology facilities at three hospitals. Medical information was extracted from charts. Univariate and multivariate comparisons of users and nonusers of CT were performed. RESULTS: A total of 526 participants (51.2%) had used CT since their diagnosis, and 357 patients (34.9%) had used CT recently (in the past 3 months). Factors that multivariate analysis found to be significantly associated (P <.05) with recent CT use were as follows: female sex; age 35 to 59 years; more education; coming to the hospital by private car; advanced disease status; having a close friend or a relative with cancer; and attending support groups or individual counseling. After controlling for these factors, individually examined psychosocial variables associated with recent CT use included the following (odds ratios [OR] with 95% confidence intervals [CI]): needs unmet by conventional medicine (OR, 2.76; 95% CI, 1.95 to 3.89); helplessness (OR, 1.39; 95% CI, 1.0 to 1.91); incomplete trust in the doctor (OR, 1.49; 95% CI, 1.08 to 2.06); and changed outlook or beliefs since the diagnosis of cancer (OR, 1.47; 95% CI, 1.07 to 2.02). Functional quality of life (including physical, emotional, social, and role function) and symptom (fatigue and diarrhea) scores were significantly worse for recent CT users compared with nonusers, controlling for age, sex, and current disease status. CONCLUSION: Characteristics associated with CT use include age, sex, education, and advanced disease. Significant associations between CT use and attending supportive psychotherapy, unmet needs, helplessness, and worse emotional and social function indicate considerable distress, suggesting that increased attention to psychosocial needs within oncologic settings is warranted.

Adolescent↗
PubMed2001

A deletion/insertion mutation in the BRCA2 gene in a breast cancer family: a possible role of the Alu-polyA tail in the evolution of the deletion.

Patients with breast and/or ovarian cancer were screened for gross rearrangements in the BRCA2 gene by Southern hybridization, with exon 10 and a fragment of exon 11 used as probes. One breast cancer patient with a positive family history had a 6.2-kb deletion including exons 12 and 13. The deletion breakpoint in intron 11 was in the 3' polyA tail of an Alu element, where a track of approximately 60 adenine nucleotide residues was inserted. Expansion of the Alu-polyA tail may have resulted from polymerase slippage during replication, representing a novel mechanism in which Alu elements mediate deletion/insertion mutations.

Adult↗
PubMed2001

Molecular properties and involvement of heparanase in cancer progression and mammary gland morphogenesis.

Tumor spread involves degradation of various components of the extracellular matrix and blood vessel wall. Among these is heparan sulfate proteoglycan, which plays a key role in the self-assembly, insolubility and barrier properties of basement membranes and extracellular matrices. Expression of an endoglycosidase (heparanase) which degrades heparan sulfate correlates with the metastatic potential of tumor cells, and treatment with heparanase inhibitors markedly reduces the incidence of metastasis in experimental animals. Heparin-binding angiogenic proteins are stored as a complex with heparan sulfate in the microenvironment of tumors. These proteins are released and can induce new capillary growth when heparan sulfate is degraded by heparanase. Here, we describe the molecular properties, expression and involvement in tumor progression of a human heparanase. The enzyme is synthesized as a latent approximately 65 kDa protein that is processed at the N-terminus into a highly active approximately 50 kDa form. The heparanase mRNA and protein are preferentially expressed in metastatic human cell lines and in tumor biopsy specimens, including breast carcinoma. Overexpression of the heparanase cDNA in low-metastatic tumor cells conferred a high metastatic potential in experimental animals, resulting in an increased rate of mortality. The heparanase enzyme also released ECM-resident bFGF in vitro, and its overexpression elicited an angiogenic response in vivo. Heparanase may thus facilitate both tumor cell invasion and neovascularization, two critical steps in tumor progression. Mammary glands of transgenic mice overexpressing the heparanase enzyme exhibit precocious branching of ducts and alveolar development, suggesting that the enzyme promotes normal morphogenesis and possibly pre-malignant changes in the mammary gland.

Breast↗
PubMed2001

The use of external radioactive markers in scintimammography.

In Tc-99m MIBI scintimammography, the exact localization of foci of increased tracer uptake or the exact anatomic correlation of palpated breast masses with a scintigraphic finding is difficult. The authors describe three patients with known or possible malignant breast lesions for whom the use of external radioactive markers successfully helped to provide this information, thus improving the diagnostic accuracy and guiding decision-making in the patients' treatment.

Adult↗
PubMed2001

Haplotype analysis of BRCA2 8765delAG mutation carriers in French Canadian and Yemenite Jewish hereditary breast cancer families.

The BRCA2 8765delAG mutation was previously reported in hereditary breast cancer families of French Canadian and Yemenite Jewish descent. Haplotype analysis, using six microsatellite markers that span BRCA2 and two intragenic polymorphisms, was performed on 8765delAG mutation carriers to determine if there was evidence that the mutations were identical by descent. The alleles of the microsatellite markers most closely flanking BRCA2 (D13S1697 and D13S1701) were found to be identical in state in all the mutation carriers. However, the disease-associated allele of one of the intragenic markers differed between the Yemenite Jews and French Canadian families, indicating that the 8765delAG mutation has independent origins in these two geographically and ethnically distinct populations.

BRCA2 Protein↗