Soluble guanylate cyclase isoenzymes: The expression of α1, α2, ß1, and ß2 subunits in the benign and malignant breast tumors.

Soluble guanylate cyclase (sGC) encompasses α and ß subunits. This study examined the expression of α1, α2, ß1, and ß2 subunits in the malignant and benign breast tumors using the Western blot analysis. Both benign and malignant tumors showed a significantly higher expression of the α1 subunit in comparison with normal tissues (p < 0.0001). In contrast, the expression of α2 and ß2 sGC were significantly lower in these tumors than normal tissues (p < .0015 and p < .001, p < .007 and p < .0001, respectively). The expression level of α1 sGC was significantly correlated with ER + PR+ (p < .0001). A significant correlation was also detected for sGC-α1 and -α2 expression with c-erbB2-negative status (p < .01). However, the expression level of sGC was not associated with tumor stage, tumor grade, or other clinicopathological features. In conclusion, as the expression of α1 sGC is upregulated and α2 and ß2 sGC are downregulated in malignant breast tumors. Variations in the expression of sGC isoenzymes may be suggested as an indicator to confirm the enzyme antitumor activity.

Prostate-specific antigen gene expression and telomerase activity in breast cancer patients: possible relationship to steroid hormone receptors.

Breast cancer, the most prevalent cancer among women, is a steroid hormone receptor-dependent cancer. Recently, it has been shown that telomerase and prostate-specific antigen (PSA) gene expressions are under control of steroid hormone receptors. The aim of this study was to investigate the relationship between telomerase activity and PSA gene expression with steroid hormone receptors in breast cancer patients. This study consisted of 50 women with breast benign tumors and 50 malignant (invasive) tumors. Telomerase activity was measured in tumor cytosol of samples by telomeric repeat amplification protocol (TRAP) assay. PSA protein and its mRNA expression were measured using ultrasensitive immunoassay and RT-PCR technique in all tumor tissues, respectively. Estrogen and progesterone receptors were stained using immunohistochemistry in tumor tissues. Telomerase activity was detected in all of the invasive breast cancer tissues. The difference of relative telomerase activity (RTA) values between stages and grades were statistically significant (p < 0.05). The PSA mRNA was detected only in benign tumors and stage I and grade I malignant tumor cytosol. Difference of tumor cytosol PSA levels between the cases and control groups and also between all grades and stages of diseases were significant (p < 0.05). There was an inverse significant correlation between the RTA and PSA protein levels in the case groups (r = -0.42, p < 0.05). There was a statistically significant difference between ER/PR with PSA level and telomerase activity in tumor tissues (p < 0.05). It is speculated that differential expression of PSA and telomerase genes in breast tumors are under control of steroid hormone receptors and could be used as a target for treatment in the future.

Suppression of tumor growth and metastasis in Mgat5-deficient mice.

Golgi beta1,6N-acetylglucosaminyltransferase V (MGAT5) is required in the biosynthesis of beta1,6GlcNAc-branched N-linked glycans attached to cell surface and secreted glycoproteins. Amounts of MGAT5 glycan products are commonly increased in malignancies, and correlate with disease progression. To study the functions of these N-glycans in development and disease, we generated mice deficient in Mgat5 by targeted gene mutation. These Mgat5-/- mice lacked Mgat5 products and appeared normal, but differed in their responses to certain extrinsic conditions. Mammary tumor growth and metastases induced by the polyomavirus middle T oncogene was considerably less in Mgat5-/- mice than in transgenic littermates expressing Mgat5. Furthermore, Mgat5 glycan products stimulated membrane ruffling and phosphatidylinositol 3 kinase-protein kinase B activation, fueling a positive feedback loop that amplified oncogene signaling and tumor growth in vivo. Our results indicate that inhibitors of MGAT5 might be useful in the treatment of malignancies by targeting their dependency on focal adhesion signaling for growth and metastasis.

High expression of FBP1 and LDHB in fibroadenomas and invasive breast cancers.

BACKGROUND: The role of gluconeogenesis in cancer cells as the reverse pathway for glycolysis is not well known. Several studies of gluconeogenesis in cancer cells still show conflicting results. Expression of key enzymes such as FBP1 and LDHB in cancer tissues may explain the role of gluconeogenesis in tumor development. OBJECTIVE: This study aimed to analyze the expression of FBP1 and LDHB in fibroadenomas and invasive cancers of the breast. METHODS: The immunohistochemical staining technique was used to show the expression of FBP1 and LDHB in formalin-fixed, paraffin-embedded blocks of 32 fibroadenomas and 31 invasive breast cancer samples. RESULTS: FBP1 was expressed by the majority of fibroadenoma (68.7%) and invasive breast cancer (71%) samples. LDHB expression in fibroadenomas was significantly higher than in invasive breast cancers (P = 0.029). The expression of these two enzymes was found in invasive, lobular, and tubular breast carcinoma, and at well, moderately, and poorly differentiated breast malignancy. CONCLUSIONS: High expression of FBP1 and LDHB was found in fibroadenomas and invasive breast cancers. A higher level of LDHB expression was observed in fibroadenomas. These results may indicate the enzymes' role in the pathogenesis of both breast diseases.

[Comparison of plasma matrix metalloproteases 2, 3, 9 in breast carcinomas and fibroadenomas]. / Confronto dei valori plasmatici delle metalloproteasi della matrice 2, 3, 9 in pazienti con carcinomi e fibroadenomi mammari.

Tumor cell infiltration causes the remodelling of peritumoral tissues, determined by an increased lytic activity of extracellular matrix exerted by the neoplastic invasive phenotype. Among the principal lytic enzymes produced by tumor cells and mainly involved in invasion process there are the matrix metalloproteases (MMPs). The Authors compared the plasmatic values of MMPs 2, 3, 9 from patients with breast carcinomas and fibroadenomas in order to evaluate whether there was a significant difference between the two groups of patients. MMPs 2, 3, 9 values were quantified by ELISA test from plasma collected 24 hours before surgery in 50 breast carcinomas and 30 fibroadenomas. MMP2 mean value from the patients with carcinomas resulted significantly higher as compared to that from the patients with fibroadenomas; while for MMP 3 and 9 mean values was not possible to find a significant difference between the two groups of malignant and benign breast tumors. These data confirm the main role played by MMPs during the tumor invasion process. Therefore, it is possible to propose the future inclusion of MMP2 test, together to other biological and clinical data, for prognostic evaluation of neoplastic breast lesions.

DNA oxidation and antioxidant status in breast cancer.

PURPOSE: : Oxidant/antioxidant balance has been suggested as an important factor for initiation and progression of cancer. The objective of this study was to determine 8-hydroxydeoxyguanosine (8-OHdG) level as a marker of oxidative DNA damage, glutathione peroxidase (G-Px), and superoxide dismutase (SOD) activities as antioxidant activity, in sera from women with breast cancer. METHODS: : Forty-nine patients with malign breast tumor were included in the study. Blood samples were collected before the surgical operation. Serum level of 8-OHdG was measured with a competitive enzyme-linked immunusorbent assay kit, SOD, and G-Px activities were measured by spectrophotometric kits. RESULTS: : 8-Hydroxydeoxyguanosine level and SOD activity were found to be increased in breast cancer group as compared with control group. Glutathione peroxidase activity in the breast cancer group was lower than those in the control group. The ratio of 8-OHdG/G-Px in breast cancer patients was found to be higher than those in the controls. There were correlations between 8-OHdG and CA19-9 (r = 0.77; P < 0.01); age and G-Px (r = -0.84; P < 0.05) in the breast cancer group. CONCLUSIONS: : Data show that serum levels of 8-OHdG and SOD activities are higher in patients with breast cancer. Glutathione peroxidase activity is lower in the breast cancer group. Increased ratio of 8-OHdG/G-Px in breast cancer patients is the evidence for impaired oxidant/ antioxidant balance in breast cancer.

Expression of nm23, MMP-2, TIMP-2 in breast neoplasm in Zhengzhou Center Hospital, China.

BACKGROUND: In recent years, the carcinoma of the breast threatens to women's health heavily. Invasion and metastasis is the main reason that results in the patients death. OBJECTIVE: A prospective study is made in the center hospital of zhengzhou, in order to approach the expression of nm23, MMP-2 (Matrix metallo-proteinase-2), TIMP-2 (it's tissue-inhibitor of the metalloproteinase-2) in the breast neoplasm and the relationship with invasion and metastasis. METHODOLOGY: This study applied the immunohistochemistry technique SP method RESULTS: In fibroadenoma, ductal carcinoma in situ and invasive ductal carcinoma of the breast 4 groups, the positive immunostaining rate of nm23, MMP-2 and TIMP-2 have significant difference among 4 groups (p < 0.05). In the breast invasive ductal carcinoma, the expression of nm23 and TIMP-2 decreased or the expression of MMP-2 increased CONCLUSION: This suggested that invasion and metastasis is ability of the neoplasm. MMP-2 in the breast ductal carcinoma in situ appears of high expression and this suggested that the positive expression of this onco-proteins was the early incident in the genetic course of the breast cancer The unite detection of nm23, MMP-2 and TIMP-2 expression would contribute to the early diagnosis and prognostic assessment of the carcinoma of the breast.

Focal adhesion proteins as markers of malignant transformation and prognostic indicators in breast carcinoma.

Focal adhesion kinase (FAK) is one of the central signaling molecules found at focal adhesion sites, which are specific areas on the cell membrane where cells attach to extracellular matrix proteins. Focal adhesion kinase interacts with multiple signaling and adaptor molecules and effects several signaling pathways. Overexpression of FAK and its substrate c-Src has been implicated in malignant transformation and acquisition of an invasive tumor phenotype of different tissues. Overexpression of the multidomain protein paxillin, which is also a FAK ligand and a c-Src substrate, has been associated with less malignant tumor behavior. The purpose of this study was to analyze the involvement of integrin signaling molecules FAK, c-Src, and paxillin in malignant transformation of the breast epithelium. Using phosphospecific antibodies FAK-pY(397) and Src-pY(416), we demonstrated that neither activation of FAK nor activation of c-Src correlates with development of invasive tumor properties. However, activation of both FAK and c-Src correlates with malignant transformation. We further demonstrated that overexpression of paxillin also correlates with malignant transformation and is a marker of a less invasive tumor phenotype. Using tissue microarray, we demonstrated that expression and activation of paxillin inversely correlated with lymph node metastases and lymphovascular invasion, respectively. No correlation between paxillin expression and activation and tumor grade, estrogen, progesterone, and Her2/Neu receptor expression was found. In summary, focal adhesion proteins FAK and c-Src can be used as markers of malignant transformation in epithelial cells but not invasive phenotype, whereas expression and activation of paxillin may represent a good prognosticator in breast carcinoma.

Telomerase activity in human breast tumors.

BACKGROUND: The activity of the ribonucleoprotein enzyme telomerase is not detected in normal somatic cells; thus, with each cell division, the ends of chromosomes consisting of the telomeric repeats TTAGGG progressively erode. The current model gaining support is that telomerase activity in germline and immortal cells maintains telomere length and thus compensates for the "end-replication problem." PURPOSE: Our objective was to determine when telomerase activity is reactivated in the progression to malignant breast cancer and if knowledge of telomerase activity may be an indicator for the diagnosis and potential treatment of breast cancer. METHODS: Using a polymerase chain reaction-based telomerase activity assay, we examined telomerase activity in 140 breast cancer specimens (from 140 patients), four phyllodes tumors (from four patients), 38 noncancerous lesions (20 fibroadenomas, 17 fibrocystic diseases, one gynecomastia; from 38 patients), and 55 adjacent noncancerous mammary tissues (from 55 of the 140 breast cancer patients). In addition, 33 fine-needle-aspirated breast samples (from 33 patients) were analyzed. RESULTS: Among surgically resected samples, telomerase activity was detected in 130 (93%) of 140 breast cancers. Telomerase activity was detected in 68% of stage I primary breast cancers, in 73% of cancers smaller than 20 mm, and in 81% of axillary lymph node-negative cancers. Moreover, the activity was detected in more than 95% of advanced stage tumors but in only two (4%) of 55 adjacent noncancerous tissues. While telomerase activity was not detected in any of 17 specimens of fibrocystic disease, surprisingly low levels of telomerase activity were detected in nine (45%) of 20 fibroadenomas. Among samples obtained by fine-needle aspiration, 14 (100%) of 14 patients whose fine-needle-aspirated specimen contained telomerase activity and who subsequently underwent surgery were confirmed to have breast cancer. Multivariate analysis of 125 specimens from patients for whom data were available on age at surgery, stage of disease, tumor size, lymph node status tumor histology, and menopausal status indicated that stage classification exhibited the strongest association with telomerase activity (for stage I versus stages II-IV: odds ratio = 1.0 versus 73.4; 95% confidence interval = 2.0-959.0; P = .02). CONCLUSION: Telomerase activity was detected in more than 95% of advanced stage breast cancers. It was absent in 19%-32% of less advanced cancers. Since a determination of any association between telomerase activity and patient survival is not possible at the present time, it remains to be determined whether lack of telomerase activity predicts for favorable outcome.

Significance of inducible nitric oxide synthase expression in benign and malignant breast epithelium: an immunohistochemical study of 151 cases.

The role of calcium independent inducible nitric oxide synthase (iNOS) in breast carcinoma is controversial, and the implications of iNOS expression on prognosis are not known. In this study, we aimed to investigate the significance of immunohistochemical iNOS expression in 100 invasive ductal carcinomas. In addition, 11 normal breast tissues, 20 cases of usual ductal hyperplasias (UDHs) and 20 fibroadenomas were included. We found that 78% of malignant and 75% of benign cases showed iNOS immunoreactivity. However, the intensity and the quantity of iNOS expression were significantly higher in the cancer group when compared with benign breasts (P<0.001), suggesting a role of iNOS in breast carcinogenesis. We were unable to show a correlation between iNOS expression and tumor grade, axillary lymph node status, and estrogen receptor expression. In 50 axilla negative cases having 5--12 years follow-up, disease free survival (DFS) rate was significantly lower in cases showing strong iNOS expression (P=0.05). As strong iNOS expression was correlated with short DFS, we concluded that further studies would be necessary to elucidate if iNOS expression might be a useful prognostic marker in breast carcinoma, especially in the axilla negative group.

Immunolocalization of aromatase and other steroidogenic enzymes in human breast disorders.

Numerous studies have shown that human breast cancer tissue has the potential to synthesize estrogen through aromatization, which may act as a local growth factor of hormone-dependent cancer cells. This study was performed to localize the site of aromatization in human breast disorders by immunohistochemistry and correlate the findings with steroid receptors, clinicopathological findings, and other steroidogenic enzymes. Specimens from 60 cases of breast disorders, including 33 cases of breast cancer and 27 cases of benign proliferative disorders, were studied immunohistochemically for aromatase. In the carcinoma cases estrogen receptor (ER) and progesterone receptor (PgR) status was determined by enzyme immunoassay and immunohistochemistry, and other steroidogenic enzymes, including P450scc (side-chain cleavage), 3 beta HSD (hydroxysteroid dehydrogenase), and P450c17, were immunolocalized. Aromatase was immunolocalized in interstitial cells and adipocytes as well as other cells in both benign and malignant breast tissues. However, strong immunoreactivity was observed in adipocytes adjacent to carcinoma in all carcinoma cases and in interstitial or stromal cells around carcinomatous glands in 20 carcinoma cases. Intratumoral staining for aromatase did not correlate significantly with age, clinical stage, histopathological type, lymph nodes metastasis, or ER and PgR status. P450scc and 3 beta HSD were focally observed in 18 and 12 cases of carcinoma, respectively, but P450c17 was never observed. Aromatase expression in stromal or interstitial cells, including adipocytes, in breast cancer may be induced by carcinoma cells and locally synthesized estrogens could function as paracrine hormones. Intratumoral aromatase in human breast neoplasms correlated with malignant phenotypes but not with ER status or prognostic parameters, suggesting that other synthetic systems probably generate any biologically significant locally synthesized estrogens in hormone-dependent breast malignancy.

Telomerase expression in human breast cancer with and without lymph node metastases.

Telomerase is a ribonucleoprotein enzyme that synthesizes telomeric DNA onto the ends of chromosomes, thereby preventing the replication-dependent shortening of these ends. Telomerase activity is detected in a wide range of cancers of various tissues, and its expression may be a critical step in tumor progression. The telomeric repeat amplification protocol was used to compare telomerase activity in breast cancers with and without lymph node metastases, as well as in fibroadenomas and normal breast tissue. Expression of telomerase was detected in 22 (79%) of 28 primary breast cancers, which included 16 (73%) of 22 cancers positive and 6 (100%) of 6 cancers negative for axillary lymph node metastases. It was detected in 1 (11%) of 9 fibroadenomas but was negative in 13 normal breast tissues. There was no statistical difference in expression of telomerase between axillary node-negative primary breast cancers and similar tumors with nodal metastasis (P = .289). Further, no statistical association was found between telomerase activity and tumor size (P = .679) or hormonal status (P = .178). The difference in telomerase activity among breast cancers vs fibroadenomas and normal breast tissues, however, was statistically significant (P < .001). Although normal breast tissue does not express telomerase, both node-positive and node-negative breast cancers express telomerase. The possible significance of telomerase expression in fibroadenomas remains open to further investigation.

Antioxidant profile in the circulation of patients with fibroadenoma and adenocarcinoma of the breast.

OBJECTIVES: To correlate the extent of lipid peroxidation with the antioxidant status in the circulation of patients with fibroadenoma and adenocarcinoma of the breast. DESIGN AND METHODS: Ten fibroadenoma and thirty breast cancer patients and an equal number of age- and sex- matched normal subjects were chosen for the study. Lipid peroxidation as evidenced by thiobarbituric acid reactive substances (TBARS) and the status of the antioxidants superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione S-transferase (GST) ascorbic acid and vitamin E were estimated. RESULTS: Enhanced lipid peroxidation with concomitant depletion of antioxidants was observed in breast cancer patients as compared to normal subjects and fibroadenoma patients (p < 0.05). A similar pattern of changes was seen in fibroadenoma patients as compared to corresponding normal subjects (p < 0.05). CONCLUSION: This study has revealed an imbalance in the redox status in patients with fibroadenoma and adenocarcinoma of the breast.

Expression of cyclooxygenase-2 in malignant and benign breast tumors.

Cyclooxygenase-2 (COX-2) is reported to play an important role in carcinogenesis. We examined COX-2 expression in patients with breast cancer and benign breast tumors. Immunohistochemical staining revealed a high level of COX-2 expression in malignant lesions of invasive ductal carcinoma (IDC) at a rate of 40% and a low level of expression in 15% of adjacent normal-appearing breast epithelia. Similarly, in ductal carcinoma in situ (DCIS), a high level of COX-2 expression was found in 80% of malignant lesions and a low level of expression in 50% of normal epithelia. Reverse transcriptional polymerase chain reaction (RT-PCR) performed in 7 of these cases disclosed that COX-2 expression was restricted to the malignant lesion. Further, all 10 cases of fibroadenoma and 10 cases of intraductal papilloma, both of which are benign tumors, had a high level of COX-2 expression. When overexpression of COX-2 was analyzed in relation to the clinicopathological features of the patients, no characteristic correlation was noted. Our results demonstrated that COX-2 is expressed in mammary tissue during tumorigenesis of the breast gland, suggesting that the cyclooxygenase isoenzyme may be a target for the prevention and treatment of breast cancer.

Localization of mineralocorticoid receptor and 11 beta-hydroxysteroid dehydrogenase type II in human breast and its disorders.

Mineralocorticoid receptors have been detected in the normal human breast and breast cancers. The expression of mineralocorticoid receptor (MR) and 11 beta-hydroxysteroid dehydrogenase type II (11sHSD2), which confers specificity on MR for aldosterone, was examined by immunohistochemistry in 114 samples from normal human breast and benign and malignant breast lesions in order to study its possible biological significance. MR and 11sHSD2 were immunolocalized in the ductal epithelium in 39/40 (98%) and 36/40 cases (90%) of normal breast, 21/22 (95%) and 15/22 cases (68%) of fibrocystic changes, and 11/11 (100%) and 8/11 (73%) cases of fibroadenoma, respectively. Cases positive for 11 sHSD2 also expressed MR but the patterns of expression varied greatly among examples of normal breast and benign breast diseases. There was a significant correlation between labeling indices of MR and 11sHSD2 in normal breast (p < 0.01) and in benign breast disease (fibrocystic change (p < 0.05) and fibroadenoma (p < 0.05)). In invasive carcinomas, immunoreactivity for MR and 11sHSD2 was detected in malignant cells in 32/41(78%) and 16/41(39%) cases. Both MR and 11sHSD2 labeling indices were significantly higher in invasive ductal carcinoma (22 cases) than invasive lobular carcinoma (19 cases) (p < 0.01). There was a significant correlation between labeling indices of MR and 11sHSD2 when analyzing all infiltrating carcinomas (p < 0.01), but not when assessing invasive lobular or invasive ductal carcinomas separately. These results indicate that the 11 sHSD2 enzyme generally colocalizes with the MR in the ductal epithelial cells of human breast, which may allow aldosterone to occupy its physiological receptor, and the expression of MR and 11sHSD2 appears to be related to ductal differentiation of breast carcinomas.

A comparison of the pattern of cathepsin-D expression in fibroadenoma, fibrocystic disease, preinvasive and invasive ductal breast carcinoma.

In the metastatic process, proteolytic enzymes play an important role in mediating the passage of cancer cells through the basement membrane and extracellular matrix. We have compared cathepsin-D (CD) expression in a range of benign and malignant breast lesions so as to investigate its role in breast cancer progression. One hundred and sixty-two breast samples, comprising 18 fibroadenomas, 22 fibrocystic disease, 96 invasive ductal carcinoma and 26 lesions with intraductal carcinoma components, were evaluated for CD expression by the standard avidin-biotin-immunoperoxidase complex method on formalin-fixed, paraffin-embedded histological sections using a commercial antibody against human cathepsin-D. Of the invasive ductal carcinomas, 61.5% showed stromal cell CD positivity, whereas 48.9% expressed CD positivity in neoplastic cells. There was significant correlation between neoplastic cell and stromal CD positivity. The prevalences of CD positivity in both neoplastic and stromal cell components were significantly higher (P < 0.05 and P < 0.01, respectively) in histological grade III tumors compared to grades I and II carcinomas. CD expression by either neoplastic or stromal cells did not show significant correlation with patient age and tumor size. Only 15% of intraductal carcinomas were CD positive and expression was limited to neoplastic cells. Neither epithelial nor stromal cells in fibrocystic lesions and fibroadenomas were CD positive, but a weak to moderate positivity was observed within myoepithelial cells in mammary ducts. These findings provide insights into the mechanism whereby tumors with high histological grade mediate invasion into tissue. The role of stromal cells in tumor progression and the means of their recruitment deserve further study.

Enzymes of carbohydrate metabolism in human breast carcinoma: relationship with serum hormones.

The enzymes involved in carbohydrate metabolism and their relationship with circulating estradiol (ET2) and prolactin (Prl) were studied in premenopausal and postmenopausal women with fibroadenoma and carcinoma of breast. The activities of all the glycolytic enzymes studied were increased in breast carcinoma tissues except for glyceraldehyde-3-phosphate dehydrogenase which showed decreased activity. Among the glycolytic enzymes studied, hexokinase, phosphofructokinase and glucose-6-phosphate dehydrogenase were found to be stimulated by elevated levels of serum ET2 and further stimulated by a simultaneous increase in Prl. However, the activity of lactate dehydrogenase was more specifically stimulated by Prl rather than ET2. None of the glycolytic enzymes studied was altered in fibroadenoma breast tissues.

Quantitative determination of telomerase activity in breast cancer and benign breast diseases.

Telomerase plays an important role in maintaining the stability of chromosomes. This ribonucleoprotein prevents chromosome ends (telomeres) from gradual loss with each cell division. It enables tumor cells to maintain telomere length, allowing indefinite replicative capacity. Telomerase activity has been detected in the majority of tumor and germ cells and in immortalized cell lines. Quantitative telomerase PCR-ELISA (TeloTAGGG Telomerase PCR ELISA(PLUS)) was evaluated for distinguishing benign and malignant breast tissue. Activity of telomerase was determined in 27 samples of fibrocystic and dysplastic tissues, 28 fibroadenomas and phylloid tumors, and 154 breast cancer tissues; 59 specimens were analyzed retrospectively. Analytical precision and linearity of the assay was tested using breast carcinoma cell line ZR-75-1 and breast tumor tissue extracts. About 4% of tumor samples were excluded from analysis due to interferences in the PCR reaction. Relative telomerase activity differed significantly in the groups of dysplastic tissues, fibroadenomas and carcinomas. The highest activity was found in breast cancer tissue. This method can identify breast cancer tissue with 73% clinical sensitivity and 93% specificity as compared to benign breast tumors. We did not find a correlation between telomerase activity and the tissue levels of estrogen and progesterone receptors, HER-2/neu oncoprotein concentration, tumor size, and lymph node positivity. Probability of disease-free survival was significantly lower for patients with telomerase activity higher than median value. As the assay for telomerase activity has very high analytical sensitivity and high specificity for cancer cells, this routinely used method may prove useful for distinguishing malignant phenotype of breast tissues.

Plasma membrane enzymes in human breast carcinoma: relationship with serum hormones.

Alkaline phosphatase, 5'nucleotidase and gammaglutamyl transferase were studied in premenopausal and post-menopausal women with fibroadenoma and breast carcinoma tissues. The relationship of circulating estradiol (E2) and prolactin (Prl) with these enzymes was also investigated. All the three enzyme activities were found to be elevated in the breast carcinoma tissues of both pre- and postmenopausal groups. None of the membrane bound enzymes studied was altered in fibroadenoma breast tissues. The activities of all the three enzymes in breast carcinoma tissues were stimulated by the elevated level of serum Prl and further stimulated by a simultaneous increase in E2.

Augmented release of matrix metalloproteinase-9 by PKC activation in organotypic cultures of human breast cancer and adjacent normal breast tissue and fibroadenoma.

The organotypic culture technique and quantitative gelatin zymography were used to determine the expression of matrix metalloproteinase (MMP)-9 and MMP-2 in human breast cancer and adjacent normal breast tissue and fibroadenoma. MMP-9 and MMP2 were constitutively expressed in all cultures. The release of these two enzymes in breast cancer was higher than that in adjacent normal breast tissue and fibroadenoma. Administration of 12-o-tetradecanoyl- phorbol-13-acetate (TPA) increased the release of MMP-9 but not of MMP-2. This response was inhibited by protein kinase C (PKC) inhibitor (H7), transcription inhibitor (actinomycin D) and translation inhibitor (cycloheximide). Moreover, the increased level of MMP-9 by TPA in breast cancer was also higher than that in adjacent normal breast tissue and fibroadenoma. These phenomena were also observed in the DAG-treated culture. These findings suggested that the MMP-9 expression in the breast cancer tissue may be more sensitive for the PKC activation.