[Cancer of the male breast. Presentation of 4 cases].
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Biomedical subjects
Publications and source records attributed to N Biglia.
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DNA chips are small, solid supports such as microscope slides onto which thousands of cDNAs or oligonucleotides are arrayed, representing known genes or simply EST clones, or covering the entire sequence of a gene with all its possible mutations. Fluorescently labeled DNA or RNA extracted from tissues is hybridized to the array. Laser scanning of the chip permits quantitative evaluation of each individual complementary sequence present in the sample. DNA chip technology is currently being proposed for qualitative and quantitative applications, firstly for the detection of point mutations, small deletions and insertions in genes involved in human diseases or affected during cancer progression; secondly, to determine on a genome-wide basis the pattern of gene expression in tumors, as well as in a number of experimental situations. The extraordinary power of DNA chips will have a strong impact on medicine in the near future, both in the molecular characterization of tumors and genetic diseases and in drug discovery and evaluation. Quantitative applications will soon spread through all fields of biology.
Nuclear receptors regulate target gene expression in response to steroid and thyroid hormones, retinoids, vitamin D and other ligands. These ligand-dependent transcription factors function by contacting various nuclear cooperating proteins, called coactivators and corepressors, which mediate local chromatin remodeling as well as communication with the basal transcriptional apparatus. Nuclear receptors and their coregulatory proteins play a role in cancer and other diseases, one leading example being the estrogen receptor pathway in breast cancer. Coregulators are often present in limiting amounts in cell nuclei and modifications of their level of expression and/or structure lead to alterations in nuclear receptor functioning, which may be as pronounced as a complete inversion of signaling, i.e. from stimulating to repressing certain genes in response to an identical stimulus. In addition, hemizygous knock-out of certain coactivator genes has been demonstrated to produce cancer-prone phenotypes in mice. Thus, assessment of coactivator and corepressor expression and structure in tumors may turn out to be essential to determine the role of nuclear receptors in cancer and to predict prognosis and response to therapy.
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BACKGROUND: Biological markers capable of predicting the risk of recurrence and the response to treatment in breast cancer are eagerly awaited. Estrogen and progesterone receptors (ER, PgR) in tumor cells mark cancers that are more likely to respond to endocrine treatment, but up to 40% of such patients do not respond. Here, the expression of a group of estrogen-regulated genes, previously identified by microarray analysis of in vitro models, was measured in breast tumors and possible associations with other clinicopathological variables were investigated. METHODS: The expression of CD24, CD44, HAT-1, BAK-1, G1P3, TIEG, NRP-1 and RXRalpha was measured by quantitative real-time RT-PCR on RNA from eighteen primary breast tumors. Statistical analyses were used to identify correlations among the eight genes and the available clinicopathological data. RESULTS: Variable expression levels of all the genes were observed in all the samples examined. Significant associations of CD24 with tumor size, CD44 with lymph node invasion, and HAT-1 and BAK-1 with ER positivity were found. The possible combinatorial value of these genes was assessed. Unsupervised hierarchical clustering analysis demonstrated that the expression profile of these genes was able to predict ER status with an acceptable approximation. CONCLUSIONS: Eight novel potential markers for breast cancer have been preliminarily characterized. As expected from in vitro data, their expression is able to discriminate ER- versus ER+ tumors.
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One major problem in primary breast cancer is the identification of new parameters able to select patients at high risk of recurrence. Our study was aimed at detecting mammary tumor cells in the bone marrow of breast cancer patients using a single bone marrow sampling and the monoclonal antibody AB/3. This antibody recognizes a membrane carbohydrate epitope present in human breast cancer cells but not in normal tissues. Only 2 out of 45 breast cancer patients were found to have a bone marrow positive AB/3 staining reaction. Our data confirm and extend previous reports that single bone marrow sampling coupled with immunocytochemistry is not sensitive enough to be used as a routine procedure to acquire prognostic information in breast cancer.
Tamoxifen is actually considered the drug of choice for the hormonal treatment of early and metastatic breast cancer due to its efficacy and low toxicity. In addition, clinical trials of adjuvant therapy have demonstrated a 35% decrease in controlateral breast cancer in women receiving tamoxifen compared with controls, suggesting a potential role for this drug in chemoprevention of breast cancer in healthy women at increased risk of disease. Although tamoxifen is usually classified as an estrogen antagonist it also has partial estrogenic effects in some tissues such as liver, bone and uterus. The estrogenic action of tamoxifen on lipid metabolism and bone mineral density suggests additional benefits in protection against cardiovascular diseases and osteoporosis in postmenopausal women. Of particular interest could be the use of tamoxifen as an alternative to traditional estrogen replacement therapy in postmenopausal women previously treated for breast cancer or at increased risk of disease due to family history or histology on breast biopsy. The potential adverse effects of tamoxifen are partially similar to those of ERT and includes an increased risk of endometrial cancer, hepatic diseases, thromboembolic alterations and ocular toxicity. The mechanism of action of tamoxifen is briefly examined and the potential toxic effects and benefits of tamoxifen treatment are discussed.
BACKGROUND: Tissue Polypeptide-specific Antigen (TPS) and CA 15.3 are two of the most widely studied tumor markers in the serum of breast cancer patients. TPS is a tumor associated proliferative marker which belongs to the cytoskeleton. CA 15.3 is a high molecular weight glycoprotein of clinical relevance in the monitoring of treatment and the detection of recurrence in breast cancer patients. PATIENTS AND METHODS: Serum values of TPS and CA 15.3 were measured in a prospective series of patients with primary breast cancer (n=267) and benign breast disease (n=46). The cut-off levels (95% specificity) determined for each test were 80 U/I for TPS and 30 k/U/l for CA 15.3. RESULTS: The diagnostic sensitivity was 0.31 for TPS and 0.32 for CA 15.3 for the detection of breast cancer. Serum TPS levels in breast cancer patients showed a relatively low positivity rate (33%), which was comparable with that of CA 15.3. Higher concentrations of TPS were found in cases with locally more advanced disease as well as in G3 tumors. By contrast, CA 15.3 basal levels were solely related to tumor size and nodal involvement. TPS and CA 15.3 levels were not related to estrogen and progesterone receptor status, peritumoral vessel invasion, multifocality and the in situ component of the tumor. After primary treatment, 20 patients developed distant metastases. In metastatic breast cancer patients TPS was more frequently and more markedly elevated than CA 15.3. In progressive disease, elevated values of TPS and CA 15.3 were found in 85% and 50%, respectively. The mean lead time was 10 months for TPS and 14 months for CA 15.3. Increasing values of TPS were independent of the site of metastasis, whereas elevated levels of CA 15.3 were mainly related to visceral metastasis. Local recurrences were usually associated with low levels of TPS and CA 15.3. By contrast, elevated values of TPS in locally recurred cases indicated rapidly progressive disease. CONCLUSIONS: Our study indicates that TPS and CA 15.3 are not helpful in distinguishing patients with breast cancer from patients with benign breast lesions. Nevertheless, at the time of diagnosis increased serum levels of the markers may facilitate the selection of high risk patients for whom additional treatment and careful follow up studies should be undertaken. Furthermore, TPS seems to be a reliable tumor marker for the early diagnosis of metastatic breast carcinoma independent of the site of metastasis, while increasing values of CA 15.3 are mainly related to visceral involvement.