Cytogenetic damage in circulating lymphocytes and buccal mucosa cells of head-and-neck cancer patients undergoing radiotherapy

This study evaluated cytogenetic damage by measuring the frequency of micronucleated cells (MNC) in peripheral blood and buccal mucosa of head-and-neck cancer patients undergoing radiotherapy.MNC frequencies were assessed in 31 patients before, during, and after radiotherapy, and in 17 C, healthy controls matched for gender, age, and smoking habits. Results showed no statistically significant difference between patients and controls prior to radiotherapy in cytokinesis-blocked lymphocytes or buccal mucosa cells. During treatment, increased MNC frequencies were observed in both cell types. Micronucleated lymphocyte levels remained high in samples collected 30 to 140 days after the end of treatment, while MNC frequency in buccal mucosa decreased to values statistically similar to baseline values. There is controversy over the effects of age, smoking habit, tumor stage, and/or metastasis on MNC frequency. However, increased frequency of micronucleated buccal mucosa cells was seen in patients under 60 years old and in those with tumors >4cm.In conclusion, the data show that radiotherapy has a potent clastogenic effect in Circulating lymphocytes and buccal mucosa cells of head-and-neck cancer patients, and that the baseline MNC frequency in these two tissues is not a sensitive marker for head-and neck neoplasm.

Classic and molecular cytogenetic analyses reveal chromosomal gains and losses correlated with survival in head and neck cancer patients

Purpose: Genetic biomarkers of head and neck tumors could be useful for distinguishing among patients with similar clinical and histopathologic characteristics but having differential probabilities of survival. The purpose of this study was to investigate chromosomal alterations in head and neck carcinomas and to correlate the results with clinical and epidentiologic variables.Experimental Design: Cytogenetic analysis of short-term cultures from 64 primary untreated head and neck squamous cell carcinomas was used to determine the overall pattern of chromosome aberrations. A representative subset of tumors was analyzed in detail by spectral karyotyping and/or confirmatory fluorescence in situ hybridization analysis.Results: Recurrent losses of chromosomes Y (26 cases) and 19 (14 cases), and gains of chromosomes 22 (23 cases), 8 and 20 (11 cases each) were observed. The most frequent structural aberration was del(22)(q13.1) followed by rearrangements involving 6q and 12p. The presence of specific cytogenetic aberrations was found to correlate significantly with an unfavorable outcome. There was a significant association between survival and gains in chromosomes 10 (P = 0.008) and 20 (P = 0.002) and losses of chromosomes 15 (P = 0.005) and 22 (P = 0.021). Univariate analysis indicated that acquisition of monosomy 17 was a significant (P = 0.0012) factor for patients with a previous family history of cancer.Conclusions: the significant associations found in this study emphasize that alterations of distinct regions of the genome may be genetic biomarkers for a poor prognosis. Losses of chromosomes 17 and 22 can be associated with a family history of cancer.

CDHI promoter hypermethylation and E-cadherin protein expression in infiltrating breast cancer

Background: the E-cadherin gene (CDH1) maps, at chromosome 16q22.1, a region often associated with loss of heterozygosity (LOH) in human breast cancer. LOH at this site is thought to lead to loss of function of this tumor suppressor gene and was correlated with decreased disease-free survival, poor prognosis, and metastasis. Differential CpG island methylation in the promoter region of the CDH1 gene might be an alternative way for the loss of expression and function of E-cadherin, leading to loss of tissue integrity, an essential step in tumor progression.Methods: the aim of our study was to assess, by Methylation-Specific Polymerase Chain Reaction (MSP), the methylation pattern of the CDH1 gene and its possible correlation with the expression of E-cadherin and other standard immunohistochemical parameters (Her-2, ER, PgR, p53, and K-67) in a series of 79 primary breast cancers ( 71 infiltrating ductal, 5 infiltrating lobular, 1 metaplastic, 1 apocrine, and 1 papillary carcinoma).Results: CDH1 hypermethylation was observed in 72% of the cases including 52/71 ductal, 4/5 lobular carcinomas and 1 apocrine carcinoma. Reduced levels of E-cadherin protein were observed in 85% of our samples. Although not statistically significant, the levels of E-cadherin expression tended to diminish with the CDH1 promoter region methylation. In the group of 71 ductal cancinomas, most of the cases of showing CDH1 hypermethylation also presented reduced levels of expression of ER and PgR proteins, and a possible association was observed between CDH1 methylation and ER expression ( p = 0.0301, Fisher's exact test). However, this finding was not considered significant after Bonferroni correction of p-value.Conclusion: Our preliminary findings suggested that abnormal CDH1 methylation occurs in high frequencies in infiltrating breast cancers associated with a decrease in E-cadherin expression in a subgroup of cases characterized by loss of expression of other important genes to the mammary carcinogenesis process, probably due to the disruption of the mechanism of maintenance of DNA methylation in tumoral cells.

Chromogenic in situ hybridization compared with other approaches to evaluate HER2/neu status in breast carcinomas

Human epidermal growth factor receptor 2 (HER2) has been evaluated in breast cancer patients to identify those most likely to benefit from herceptin-targeted therapy. HER2 amplification, detected in 20-30% of invasive breast tumors, is associated with reduced survival and metastasis. The most frequently used technique for evaluating HER2 protein status as a routine procedure is immunohistochemistry (IHC). HER2 copy number alterations have also been evaluated by fluorescence in situ hybridization (FISH) in moderate immunoexpression (IHC 2+) cases. An alternative procedure to evaluate gene amplification is chromogenic in situ hybridization (CISH), which has some advantages over FISH, including the correlation between HER2 status and morphological features. Other methodologies have also been used, such as silver-enhanced in situ hybridization (SISH) and quantitative real-time RT-PCR, to determine the number of HER2 gene copies and expression, respectively. Here we will present a short and comprehensive review of the current advances concerning HER2 evaluation in human breast cancer.

Evidence of epigenetic regulation of the tumor suppressor gene cluster flanking RASSF1 in breast cancer cell lines

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Triiodothyronine mimics the effects of estrogen in breast cancer cell lines

MCF-7 (estrogen receptor positive - ER(+)) and MDA-MB-231 (estrogen receptor negative - ER(-)) are human breast cancer cell lines which express functional thyroid hormone receptors (c-erb A alpha 1 and c-erb beta 1) as indicated by stimulation of mitochondrial alpha-glycerophosphate dehydrogenase. In MCF-7, mimicking E(2), T-3 stimulated growth in a dose-dependent (10(10) M-10(-8) M) manner, induced the expression of progesterone receptor and growth factor TGF alpha mRNAs and inhibited that of TGF beta mRNA; T-3 also increased progesterone binding and LDH5 isozyme activities. None of these effects were observed in (ER(-)) MDA-MB-231 cells. 10(-6) M tamoxifen (TAM) reverted growth stimulation, suppressed progesterone receptor and TGF alpha mRNA induction and restored TGF beta mRNA to control levels in T-3-treated MCF-7 cells. That T-3 is acting in MCF-7 cells via its binding to ER is suggested by the immunoprecipitation of pre-bound I-125-T-3 from MCF-7 nuclear extracts by an ER-specific monoclonal antibody and by the displacement of H-3-estradiol binding to ER by radioinert T-3. Copyright (C) 1996 Elsevier B.V. Ltd.

Spectrum of carcinoembryonic antigen immunoreactivity from isolated ductal hyperplasias to atypical hyperplasias associated with infiltrating ductal breast cancer

Aims - To study the immunohistochemical expression of carcinoembryonic antigen (CEA) in ductal hyperplasia of the breast and to investigate its putative relation with atypia and co-existing infiltrating ductal carcinoma.Methods - Paraffin wax embedded tissue from 37 cases of isolated ductal hyperplasia (five with atypia and 32 without atypia) and 25 cases of ductal hyperplasia associated infiltrating ductal carcinoma (IDC) (seven with atypia and 18 without atypia) was stained with a monoclonal anti-CEA antibody using a standard avidin biotin immunoperoxidase method.Results - CEA immunoreactivity was observed in eight (12.8%) ductal hyperplasia cases. The percentage of CEA positivity in ductal hyperplasia cases with atypia (33.3%) was substantially higher than that observed in cases of ductal hyperplasia without atypia (8.0%). Six cases of ductal hyperplasia associated IDC reacted with CEA; in these six cases the neoplastic cells of the co-existing carcinoma were also CEA positive. The percentage of CEA immunoreactivity in ductal hyperplasia associated IDC was higher than that observed in isolated ductal hyperplasia (24.0 v 5.4%). The percentage of CEA immunoreactivity in atypical ductal hyperplasia associated IDC was similar to that observed in IDC alone (42.9 v 40.0%).Conclusions-The presence of CEA immunoreactivity has been confirmed in benign proliferative breast lesions. The prevalence of such immunoreactivity increases from 3.1% in isolated, nonatypical ductal hyperplasia to 42.9% in atypical ductal hyperplasia associated IDC. This finding and the similarity of the frequency of CEA positivity in atypical ductal hyperplasia associated IDC and in IDC alone suggests that there is a pathogenetic link between ductal hyperplasia and some types of breast cancer.

CYTOGENETIC REPORT OF A MALE BREAST-CANCER

The cytogenetic findings on G-banding in an infiltrating ductal breast carcinoma in a 69-year-old man are reported. The main abnormalities observed were trisomy of chromosomes 8 and 9 and structural rearrangement in the long arm of chromosome 17 (add(17)(q25)). Our results confirm the trisomy of chromosome 8 in the characterization of the subtype of ductal breast carcinomas and demonstrate that chromosome 17, which is frequently involved in female breast cancers, is also responsible for the development or progression of primary breast cancers in males.