Prognostic and predictive value of low estrogen receptor expression in breast cancer.

PURPOSE: Anti-hormonal therapy (tamoxifen) is recommended for estrogen receptor (er)-positive breast cancer (bca); however, its effect on low-receptor cancers is unclear. We retrospectively evaluated the effect of adjuvant tamoxifen in patients with weakly er-positive bca. METHODS: We identified 2221 bca patients who had been er-tested by ligand-based assay (lba) during 1976-1995 and who had been treated and followed until 2008. Cox proportional hazards models adjusted for age, body mass index, tumour size, nodal status, surgery, and chemotherapy were used to assess the effect of er level on bca survival in patients who received tamoxifen. RESULTS: Overall, 17% (383) of patients were within 0-3 fmol/mg cytosol protein, and 12% (266) were within 4-9 fmol/mg cytosol protein. Patients with er levels of 0-3, 4-9, 10-19, 20-49, and 50 fmol/mg or more cytosol protein had 20-year bca survival rates of 56%, 56%, 63%, 71%, and 60% respectively. Of the 2221 patients studied, 661 (29.8%) received anti-hormonal therapy. Within the latter group, er levels of 0-3, 4-9, 10-19, 20-49, and 50 fmol/mg or more cytosol protein were associated with a hazard ratio for lower bca mortality: respectively, 1.00 (reference), 0.59 (p = 0.09), 0.19 (p < 0.0001), 0.26 (p < 0.0001), and 0.31 (p < 0.0001)-the risk reduction being significant only for er levels of 10 fmol/mg or more cytosol protein. CONCLUSIONS: Tamoxifen use in bca patients with a weakly positive er status (4-9 fmol/mg cytosol protein), compared with those having higher er levels (≥10 fmol/mg cytosol protein), is not associated with a significantly lower bca-specific mortality. Our results do not support treatment with anti-hormonal therapy for bca patients with a weakly positive er status as identified by lba.

Is clinical breast examination important for breast cancer detection?

BACKGROUND: Screening clinical breast examination (cbe) is controversial; the use of cbe is declining not only as a screening tool, but also as a diagnostic tool. In the present study, we aimed to assess the value of cbe in breast cancer detection in a tertiary care centre for breast diseases. METHODS: This retrospective study of all breast cancers diagnosed between July 1999 and December 2010 at our centre categorized cases according to the mean of detection (cbe, mammography, or both). A cbe was considered "abnormal" in the presence of a mass, nipple discharge, skin or nipple retraction, edema, erythema, peau d'orange, or ulcers. RESULTS: During the study period, a complete dataset was available for 6333 treated primary breast cancers. Cancer types were ductal carcinoma in situ (15.3%), invasive ductal carcinoma (75.7%), invasive lobular carcinoma (9.0%), or others (2.2%). Of the 6333 cancers, 36.5% (n = 2312) were detected by mammography alone, 54.8% (n = 3470) by mammography and cbe, and 8.7% (n = 551) by physician-performed cbe alone (or 5.3% if considering ultrasonography). Invasive tumours diagnosed by cbe alone were more often triple-negative, her2-positive, node-positive, and larger than those diagnosed by mammography alone (p < 0.05). CONCLUSIONS: A significant number of cancers would have been missed if cbe had not been performed. Compared with cancers detected by mammography alone, those detected by cbe had more aggressive features. Clinical breast examination is a very low-cost test that could improve the detection of breast cancer and could prompt breast ultrasonography in the case of a negative mammogram.

Recommendations on breast cancer screening and prevention in the context of implementing risk stratification: impending changes to current policies.

In recent years, risk stratification has sparked interest as an innovative approach to disease screening and prevention. The approach effectively personalizes individual risk, opening the way to screening and prevention interventions that are adapted to subpopulations. The international perspective project, which is developing risk stratification for breast cancer, aims to support the integration of its screening approach into clinical practice through comprehensive tool-building. Policies and guidelines for risk stratification-unlike those for population screening programs, which are currently well regulated-are still under development. Indeed, the development of guidelines for risk stratification reflects the translational aspects of perspective. Here, we describe the risk stratification process that was devised in the context of perspective, and we then explain the consensus-based method used to develop recommendations for breast cancer screening and prevention in a risk-stratification approach. Lastly, we discuss how the recommendations might affect current screening policies.

Does mammographic density reflect the expression of breast cancer markers?

Mammographic density reflects variation in breast tissue composition as detected on mammogram. It is associated with a number of well-known breast cancer risk factors and itself is considered one of the strongest risk factors for breast cancer. If the expression of several proteins and genes within the breast tissue influences mammographic density in the same way as it influences breast cancer risk, then mammographic density might serve as an intermediate biomarker in future epidemiological studies on breast cancer. This has the potential to provide a quick means for predicting the effect of changes in the breast microenvironment on breast cancer risk without having to wait for an eventual development of breast cancer. In this review, the expression of several proteins and genes (growth factors, enzymes, proteoglycans and pro-inflammatory markers) within the breast tissue is shown to be associated with mammographic density. These proteins and genes are suspected to play a role in breast carcinogenesis. More studies assessing differential expression of proteins and genes in mammary epithelium and stroma and their association with mammographic density among premenopausal and postmenopausal women are required. Identification of proteins and genes influencing mammographic density may provide further insight on the molecular causes of breast cancer.

Health-related quality of life anticipated with different management strategies for febrile neutropenia in adult cancer patients.

PURPOSE: To describe anticipated health-related quality of life (HRQL) for different hypothetical strategies of febrile neutropenia (FN) management in adult cancer patients. METHODS: Seventy-eight adult cancer patients were enrolled. Our study considered four different hypothetical treatment strategies for FN: (1) entire inpatient management with intravenous (IV) antibiotics; (2) oral treatment at home after an initial observation in hospital with IV antibiotics; (3) entire outpatient management with IV antibiotics; and (4) entire outpatient management with oral antibiotics. Initially, patients were asked to rank the different treatment strategies for FN based on their personal preference. Subsequently, HRQL was rated using visual analog scale (VAS), time trade-off (TTO), and willingness-to-pay (WTP). RESULTS: Seventy-five percent of all respondents preferred an outpatient strategy for FN (36% oral, 21% intravenous, 18% early discharge). Further, outpatient strategies were associated with higher mean VAS scores (possible range 0-10) (oral: 6.1 (standard deviation (SD) 3.1); intravenous: 6.2 (SD 2.2); early discharge: 5.7 (SD 2.1)) as compared to inpatient care (5.3 (SD 2.9)). On the aggregate level, patients were willing to give up between 9 and 10 weeks of their life (TTO; corresponding to <1% of remaining life expectancy) and to pay between $255 and $327 Canadian dollars (WTP) to avoid treatment in hospital. CONCLUSIONS: Our study indicates that the majority of adult cancer patients would prefer an outpatient strategy for FN. However, patients' preferences vary substantially at the individual level. Implementation of outpatient strategies into routine clinical practice should consider this variability.

Health-related quality of life anticipated with different management strategies for paediatric febrile neutropaenia.

BACKGROUND: To describe (1) anticipated health-related quality of life during different strategies for febrile neutropaenia (FN) management and (2) attributes of those preferring inpatient management. METHODS: Respondents were parents of children 0-18 years and children 12-18 years receiving cancer treatment. Anticipated health-related quality of life was elicited for four different FN management strategies: entire inpatient, early discharge, outpatient oral and outpatient intravenous (i.v.) therapy. Tools used to measure health-related quality of life were visual analogue scale (VAS), willingness to pay and time trade off. RESULTS: A total of 155 parents and 43 children participated. For parents, median VAS scores were highest for early discharge (5.9, interquartile range 4.4-7.2) and outpatient i.v. (5.9, interquartile range 4.4-7.3). For children, median scores were highest for early discharge (6.1, interquartile range 4.6-7.2). In contrast, the most commonly preferred strategy for parents and children was inpatient in 55.0% and 37.2%, respectively. Higher current child health-related quality of life was associated with a stronger preference for outpatient management. CONCLUSION: Early discharge and outpatient i.v. management are associated with higher anticipated health-related quality of life, although the most commonly preferred strategy was inpatient care. This data may help with determining more cost-effective strategies for paediatric FN.

Depletion of the erbB-2 gene product p185 by benzoquinoid ansamycins.

Herbimycin A, a benzoquinoid ansamycin, is widely used as an inhibitor of tyrosine kinases. We have examined the effects of herbimycin A and several analogues on p185, the tyrosine kinase encoded by the erbB2 gene in human breast cancer cells. Exposure to 0.35 microM herbimycin A reduced tyrosine phosphorylation of p185 in SKBr3 cells by 80% after 2 h, and the p185 protein level was reduced by 90% after 6 h. The reduction of p185 resulted primarily from increased degradation of p185; cellular protein synthesis was reduced only 16% in SKBr3 cells treated with herbimycin A, RNA synthesis was inhibited only 10%, and erbB2 mRNA levels were unchanged. Examination of the major cellular glycoproteins indicated that most glycoproteins were unaffected under conditions that substantially depleted p185. Studies with cell lines transfected with erbB2 containing defined deletions indicated that susceptibility to the depletion of p185 by herbimycin and its analogues required the domain encoded by amino acids 751-971. The benzoquinoid ansamycins therefore initiate a process of specific degradation of tyrosine kinases by a mechanism that remains unknown.

Induction of apoptosis and cell cycle arrest by CP-358,774, an inhibitor of epidermal growth factor receptor tyrosine kinase.

The epidermal growth factor receptor (EGFR) is overexpressed in a significant percentage of carcinomas and contributes to the malignant phenotype. CP-358,774 is a directly acting inhibitor of human EGFR tyrosine kinase with an IC50 of 2 nM and reduces EGFR autophosphorylation in intact tumor cells with an IC50 of 20 nM. This inhibition is selective for EGFR tyrosine kinase relative to other tyrosine kinases we have examined, both in assays of isolated kinases and whole cells. At doses of 100 mg/kg, CP-358,774 completely prevents EGF-induced autophosphorylation of EGFR in human HN5 tumors growing as xenografts in athymic mice and of the hepatic EGFR of the treated mice. CP-358,774 inhibits the proliferation of DiFi human colon tumor cells at submicromolar concentrations in cell culture and blocks cell cycle progression at the G1 phase. This inhibitor produces a marked accumulation of retinoblastoma protein in its underphosphorylated form and accumulation of p27KIP1 in DiFi cells, which may contribute to the cell cycle block. Inhibition of the EGFR also triggers apoptosis in these cells as determined by formation of DNA fragments and other criteria. These results indicate that CP-358,774 has potential for the treatment of tumors that are dependent on the EGFR pathway for proliferation or survival.

Inhibition of the oncogene product p185erbB-2 in vitro and in vivo by geldanamycin and dihydrogeldanamycin derivatives.

The erbB-2 oncogene encodes a transmembrane protein tyrosine kinase which plays a pivotal role in signal transduction and has been implicated when overexpressed in breast, ovarian, and gastric cancers. Naturally occurring benzoquinoid ansamycin antibiotics herbimycin A, geldanamycin (GDM), and dihydrogeldanamycin were found to potently deplete p185, the erbB-2 oncoprotein, in human breast cancer SKBR-3 cells in culture. Chemistry efforts to modify selectively the quinoid moiety of GDM afforded derivatives with greater potency in vitro and in vivo. Analogs demonstrated inhibition of p185 phosphotyrosine in cell culture and in vivo after systemic drug administration to nu/nu nude mice bearing Fisher rat embryo cells transfected with human erbB-2 (FRE/erbB-2). Specifically, dosed intraperitoneally at 100 mg/kg, 17-(allylamino)-17-demethoxygeldanamycin and other 17-amino analogs were effective at reducing p185 phosphotyrosine in subcutaneous flank FRE/erbB-2 tumors. Modifications to the 17-19-positions of the quinone ring revealed a broad structure-activity relationship in vitro.

erbB-2 oncogene inhibition by geldanamycin derivatives: synthesis, mechanism of action, and structure-activity relationships.

Overexpression of the erbB-2 oncogene has been linked to poor prognosis in breast, ovarian, and gastric cancers. Naturally occurring benzoquinoid ansamycin antibiotics herbimycin A, geldanamycin (GDM), and dihydrogeldanamycin were found to potently deplete p185, the erbB-2 oncoprotein, in human breast cancer SKBR-3 cells in culture. Chemistry efforts to modify selectively the ansa ring of GDM afforded derivatives with greater potency in vitro and in vivo. Analogs demonstrated inhibition of p185 phosphotyrosine in cell culture and in vivo after systemic drug administration to nu/nu nude mice bearing Fisher rat embryo cells transfected with human erbB-2. Functional group modification in the ansa ring was performed stereoselectively and regiospecifically without the need for protection strategies. Essential functional groups that were required for anti-erbB-2 activity were the 7-carbamate and the 2,3-double bond. Modification of the functional groups at the other positions was permitted. Structure-activity relationships are described for 1-5-, 7-9-, 11-, 15-, and 22-substituted geldanamycins.

Competitive learning with floating-gate circuits.

Competitive learning is a general technique for training clustering and classification networks. We have developed an 11-transistor silicon circuit, that we term an automaximizing bump circuit, that uses silicon physics to naturally implement a similarity computation, local adaptation, simultaneous adaptation and computation and nonvolatile storage. This circuit is an ideal building block for constructing competitive-learning networks. We illustrate the adaptive nature of the automaximizing bump in two ways. First, we demonstrate a silicon competitive-learning circuit that clusters one-dimensional (1-D) data. We then illustrate a general architecture based on the automaximizing bump circuit; we show the effectiveness of this architecture, via software simulation, on a general clustering task. We corroborate our analysis with experimental data from circuits fabricated in a 0.35-mum CMOS process.

Lactobacillus reuteri ingestion and IK(Ca) channel blockade have similar effects on rat colon motility and myenteric neurones.

BACKGROUND: We have previously shown that ingestion of Lactobacillus reuteri may modulate colonic enteric neuron activity but with unknown effects on colon motility. The aim of the present report was to elucidate the neuronal mechanisms of action of the probiotic by comparing the effects on motility of L. reuteri ingestion with blockade of a specific ionic current in enteric neurons. METHODS: We have used intraluminal pressure recordings from ex vivo rat colon segments and whole cell patch clamp recordings from neurons of rat longitudinal muscle myenteric plexus preparations to investigate the effects of L. reuteri and TRAM-34 on colon motility and neurophysiology. The effects of daily feeding of 10(9) L. reuteri bacteria or acute application of TRAM-34 on threshold fluid filling pressure or pulse pressure was measured. KEY RESULTS: Lactobacillus reuteri increased intraluminal fluid filling pressure thresholds for evoking pressure pulses by 51% from 0.47 +/- 0.17 hPa; the probiotic also decreased the pulse pressure amplitudes, but not frequency, by 18% from 3.91 +/- 0.52 hPa. The intermediate conductance calcium-dependent potassium (IK(Ca)) channel blocker TRAM-34 (3 micromol L(-1)) increased filling threshold pressure by 43% from 0.52 +/- 0.22 hPa and reduced pulse pressure amplitude by 40% from 2.63 +/- 1.11 hPa; contraction frequency was unaltered. TRAM-34 (3 micromol L(-1)) reduced membrane polarization, leak conductance and the slow afterhyperpolarization current in 16/16 myenteric rat colon AH cells but 19/19 S cells were unaffected. CONCLUSIONS & INFERENCES: The present results are consistent with L. reuteri enhancing tonic inhibition of colon contractile activity by acting via the IK(Ca) channel current in AH cells.

Metallothionein-II and ferritin H mRNA levels are increased in arsenite-exposed HeLa cells.

Arsenite is extremely toxic and, though non-mutagenic, is a carcinogen. To determine the effects of arsenite on changes in cell physiology, we searched for genes in HeLa cells whose mRNAs are more abundant after cellular exposure to arsenite. A cDNA subtraction was performed between cDNA synthesized from HeLa cells grown in the absence and presence of 5 microM sodium arsenite. Isolation and sequencing of three clones that showed a higher hybridization signal to RNA from arsenite-exposed cells, versus unexposed cells, revealed that two of the cDNAs coded for human ferritin H chain and the other coded for metallothionein-II. These results suggest the possibility that arsenite exposure may lead to increased levels of oxygen radicals, which augmented metallothionein and ferritin can act to detoxify.

Transcription of the Escherichia coli fliC gene is regulated by metal ions.

luxAB gene fusions in the Escherichia coli genome were used to screen for clones displaying transcriptional changes in the presence of aluminum. One clone was found that contained a luciferase gene fusion in which transcription was increased in the presence of aluminum and which was subsequently shown to be induced by copper, iron, and nickel. Cloning of the metal-regulated gene, hybridization to the ordered phage lambda bank of the E. coli chromosome, and sequencing of DNA adjacent to the luxAB fusion revealed that the insertion occurred within the fliC (hag) gene of E. coli. This gene encodes flagellin, the filament subunit of the bacterial motility organ, and is under the control of several regulatory cascades. These results suggest that environmental metals may play a role in the regulation of the motility potential of E. coli and that this bioluminescent gene fusion clone (or derivatives thereof) may be used to prepare a biosensor for the rapid detection of metal contamination in water samples.

An Escherichia coli chromosomal ars operon homolog is functional in arsenic detoxification and is conserved in gram-negative bacteria.

Arsenic is a known toxic metalloid, whose trivalent and pentavalent ions can inhibit many biochemical processes. Operons which encode arsenic resistance have been found in multicopy plasmids from both gram-positive and gram-negative bacteria. The resistance mechanism is encoded from a single operon which typically consists of an arsenite ion-inducible repressor that regulates expression of an arsenate reductase and inner membrane-associated arsenite export system. Using a lacZ transcriptional gene fusion library, we have identified an Escherichia coli operon whose expression is induced by cellular exposure to sodium arsenite at concentrations as low as 5 micrograms/liter. This chromosomal operon was cloned, sequenced, and found to consist of three cistrons which we named arsR, arsB, and arsC because of their strong homology to plasmid-borne ars operons. Mutants in the chromosomal ars operon were found to be approximately 10- to 100-fold more sensitive to sodium arsenate and arsenite exposure than wild-type E. coli, while wild-type E. coli that contained the operon cloned on a ColE1-based plasmid was found to be at least 2- to 10-fold more resistant to sodium arsenate and arsenite. Moreover, Southern blotting and high-stringency hybridization of this operon with chromosomal DNAs from a number of bacterial species showed homologous sequences among members of the family Enterobacteriaceae, and hybridization was detectable even in Pseudomonas aeruginosa. These results suggest that the chromosomal ars operon may be the evolutionary precursor of the plasmid-borne operon, as a multicopy plasmid location would allow the operon to be amplified and its products to confer increased resistance to this toxic metalloid.