Risk stratification by hormonal receptor (ER, PgR) and HER2 status in small (≤1cm) invasive breast cancer: Who might be a possible candidate for adjuvant treatment?

564

Background: With the increasing use of screening mammography, the proportion of ≤ 1 cm invasive breast cancer is increasing. Identification of breast cancer molecular subtypes has resulted in a better appreciation of the biologic heterogeneity, which is not fully explained by clinicopathologic features including staging system. The aims of this study were: 1) to identify the risk factors of systemic metastases in patients with ≤ 1 cm invasive breast cancer and 2) to investigate the patients group at greatest risk of such failure even in these small tumors. Method: Data were collected retrospectively in the breast cancer registry of our institution for patients with invasive breast cancer from October 1994 to December 2004. Results: Of 4,036 patients who received curative breast cancer surgery, 466 patients who had T1a or T1b breast cancer were identified. 39 patients who received neoadjuvant chemotherapy were excluded in this study. Ipsilateral axillary lymph node involvement was found in 13% (57/427) at the time of surgery. Axillary lymph node involvement was much more common in HER-2 positive group (33% vs 11%, p < 0.0001) and triple negative (TN) group (24% vs 11%, p = 0.002) than in hormone receptor positive group. During median 61 months of follow-up, overall 10 year estimated distant relapse-free survival (DRFS) and overall survival (OS) were 95% and 92%, respectively. Multivariate analysis was conducted in 370 (T1aN0, T1bN0) patients, who had no lymph node involvement. In Cox-regression model, HER-2 positivity and triple negativity were identified as independent prognostic factors to predict DRFS [Hazard ratio (HR) 8.8, p = 0.003 for HER-2 positive group; HR 5.1, p = 0.026 for TN group] and OS (HR 5.0, p = 0.067 for HER-2 positive group; HR 11.1, p = 0.017 for TN group) in T1bN0 tumors. Limiting to T1aN0 tumors, statistical significance was not maintained. Conclusions: Even though T1aN0 and T1bN0 tumors have been known to have a relative low risk of systemic failure, anti-HER-2 directed therapy for HER-2 positive group and new innovative adjuvant systemic treatment for TN group in patients with T1bN0 tumor should be considered. Prospective adjuvant trials should be warranted in these subgroups of patients.

No significant financial relationships to disclose.

HMPS (2-hydroxy-4-methoxyphenylstilbene), a stilbene derivative of rhapontigenin, and cell death by mitochondrial apoptotic pathway in breast cancer cells

e22130

Background: Breast cancer with resistance to clinical therapy is a significant threat to live of recurrent breast cancer patients, and chemo-resistant breast cancer is increasing rapidly. During last several decades, natural stilbenoids have been studied on anticancer effects in vitro and in vivo, and resveratrol is the most famous stilbene as a leading compound in the studies of anticancer compounds derived from plants. HMPS (2-hydroxy-4-methoxyphenylstilbene) is an analogue derived from rhapontigenin (3,5,3'-trihydroxy-4'-methoxy-trans-stilbene), which is a stilbene of herbal plant Rheum undulatum. TMS (2,3',4,5'-tetramethoxystilbene), an another stilbene analogue from rhapontigenin, was reported potent anticancer effect on tamoxifen-resistant MCF-7 cells. In this study we investigated inhibitory effect of HMPS on proliferation of breast cancer and a potential for a new therapeutic candidate. Methods: We examined cell viability of MCF-7 and MDA-MB-231 by MTT assay after exposure to various concentrations of HMPS. Apoptotic cell death induced by HMPS was investigated by florescence microscopy, cell cycle analysis and western blotting. Results: Cell viability of breast cancer cells after 24 h exposure to HMPS decreased significantly, and both ER-positive and ER-negative breast cancer cells responded to HMPS. HMPS induced nucleus fragmentation and G2/M arrest followed by sub-G1 accumulation of apoptotic cells in time- and dose-dependent manner. During the process of cell death induced by HMPS, mitochondrial membrane potential was disturbed and caspase-3 and PARP cleavage were observed. Moreover, HMPS decreased cell number of LTED MCF-7 cells(Long term estradiol deprived cell) effectively. Conclusions: Our results demonstrates that proliferation inhibitory effect of HMPS is about 50-fold more potent than those of rhapontigenin and furthermore HMPS also inhibits cell growth of LTED cells which are difficult to treat therapeutic agents. Therefore, HMPS may be a potential therapeutic candidate to treat the recurrent breast cancer by alone or combination with other conventional anticancer agents.

No significant financial relationships to disclose.

Increased phonon scattering by nanograins and point defects in nanostructured silicon with a low concentration of germanium

The mechanism for phonon scattering by nanostructures and by point defects in nanostructured silicon (Si) and the silicon germanium (Ge) alloy and their thermoelectric properties are investigated. We found that the thermal conductivity is reduced by a factor of 10 in nanostructured Si in comparison with bulk crystalline Si. However, nanosize interfaces are not as effective as point defects in scattering phonons with wavelengths shorter than 1 nm. We further found that a 5 at. % Ge replacing Si is very efficient in scattering phonons shorter than 1 nm, resulting in a further thermal conductivity reduction by a factor of 2, thereby leading to a thermoelectric figure of merit 0.95 for Si95Ge5, similar to that of large grained Si80Ge20 alloys.

Optical spectroscopy of superconducting Ba0.55K0.45Fe2As2: evidence for strong coupling to low-energy bosons

Normal state optical spectroscopy on single crystals of the new iron arsenide superconductor Ba0.55K0.45Fe2As2 shows that the infrared spectrum consists of two major components: a strong metallic Drude band and a well-separated midinfrared absorption centered at 0.7 eV. It is difficult to separate the two components unambiguously but several fits using Lorentzian peaks suggest a model with a Drude peak having a plasma frequency of 1.6 to 2.1 eV and a midinfrared peak with a plasma frequency of 2.5 eV. Detailed analysis of the frequency dependent scattering rate shows that the charge carriers interact with a broad bosonic spectrum extending beyond 100 meV with a very large coupling constant lambda=3.4 at low temperature. As the temperature increases this coupling weakens to lambda=0.78 at ambient temperature. This suggests a bosonic spectrum that is similar to what is seen in the lower Tc cuprates.

Mechanisms that limit the light stimulus frequency following through the DL-2-amino-4-phosphonobutyric acid sensitive and insensitive rod Off-pathways

In the retina, rod signal pathways process scotopic visual information. Light decrements are mediated by two distinct groups of rod pathways in the dark-adapted retina that can be differentiated on the basis of their sensitivity to the glutamate agonist dl-2-amino-4-phosphonobutyric acid (APB). We have found that the APB sensitive and insensitive rod Off-pathways signal different light decrement information: the APB sensitive rod Off-pathway conveys slow and low frequency light signals, whereas the APB insensitive rod Off-pathways mediate fast and high frequency light signals [Wang GY (2006) Unique functional properties of the APB sensitive and insensitive rod pathways signaling light decrements in mouse retinal ganglion cells. Vis Neurosci 23:127-135]. However, the mechanisms which limit the frequency following through the APB sensitive and insensitive rod Off-pathways remain unknown. In the current study, whole-cell patch-clamp recordings were made from ganglion cells in dark and light adapted mouse retina to identify the mechanisms that limit the frequency following through the APB sensitive and insensitive rod Off-pathways. The results showed that the sites from AII amacrine cells to Off cone bipolar cells are the major mechanisms that limit the frequency following through the APB sensitive rod Off-pathway. In the APB insensitive rod Off-pathways, rods themselves limited the frequency following through these pathways. Moreover, ganglion cells were able to follow higher frequencies under photopic conditions than under scotopic conditions. The Off responses followed lower frequencies than On responses under photopic conditions. This finding was observed in cells that yielded On or Off responses only as well as in On-Off cells.

46, XX male sex reversal syndrome: a case report and review of the genetic basis

Sex reversal syndrome is a kind of human genetic disease about gender dysplasia, which is characterised by inconsistency between gonadal sexuality and chromosome sexuality; the incidence rate was about 1:20,000-100,000. The clinical manifestations, hormonal levels and cytogenetic findings in a patient of 46, XX male sex reversal syndrome retrospectively were analysed and related published reports were reviewed. The DNA fragments of sex-determining region Y (SRY) gene from the patient was found by polymerase chain reaction, but the fluorescent in situ hybridisation analysis revealed that the SRY translocated from Y to X chromosome. We concluded that the Y chromosomal SRY gene is required for the regulation of male sex determination. The detection of SRY is important for the clinical diagnosis of sex reversal syndrome. Translocation of SRY to X chromosome or other autosomes would be one of the key factors that induced XX male SRS.

An optimised, small-scale preparation of high-quality RNA from dry seeds of Davidia involucrata

INTRODUCTION

The dormancy of Davidia involucrata seeds normally lasts for an extended period of time and because of this unique property the species is an excellent model for studying the molecular mechanisms of plant dormancy. The use of minimal plant material is desirable for RNA extraction since D. involucrata is a rare plant and it is relatively difficult to collect large amounts of seeds in order to perform molecular biology studies.

OBJECTIVE

To improve the quality of RNA obtained from seeds of D. involucrata by eliminating the oxidation of polyphenols during extraction and by preventing polysaccharides and other impurities from being extracted.

METHODS

A previously described method was modified by the addition of 4% (w/v) poly(N-vinyl-2-pyrrolidone) to the dry seeds during grinding and by adding 5% (v/v) beta-mercaptoethanol and 28% (v/v) ethanol to the extraction buffer. Two further centrifugation steps (5000 and 8000 rpm) were utilised and one-seventh volume of ethanol was incubated with the supernatant at 4 degrees C for 2-3 h prior to the precipitation of RNA.

RESULTS

Following these modifications, an effective method was established for total RNA extraction from a small amount of dry seeds of D. involucrata. The isolated RNA was shown to have high purity and integrity by gel electrophoresis and spectrophotometry, and was confirmed to be suitable for RT-PCR and the construction of cDNA libraries.

CONCLUSION

The modified method reduced the amount of seeds required for extraction of total DNA and was beneficial for preserving the endangered species.

The single-macro domain protein LRP16 is an essential cofactor of androgen receptor

LRP16 is a special member of the macro domain superfamily, containing only a stand-alone macro domain functional module. Previous study demonstrated that the estrogenically regulated LRP16 cooperates with the estrogen receptor alpha and enhances the receptor's transcriptional activity in an estrogen-dependent manner. Here, we discovered that LRP16 binds to androgen receptor (AR) via its macro domain and amplifies the transactivation function of AR in response to androgen. Similarly, we also discovered that LRP16 acts as a potential coactivator to amplify the transactivation of at least other four nuclear receptors (NRs). Importantly, we show that the single macro domain in LRP16 can serve as the AR coactivator. RNA interference knockdown of LRP16 leads to impaired AR function and greatly attenuates the coactivation of AR by other AR coactivators such as ART-27 and steroid receptor coactivator-1. This interference also markedly inhibits the androgen-stimulated proliferation of androgen-sensitive LNCaP prostate cancer cells. However, LRP16 knockdown did not significantly affect the growth rate of AR-negative PC-3 prostate cancer cells. Furthermore, we observed the induction effect of LRP16 expression by androgen and established a feedforward mechanism that activated AR transactivation. Our results suggest that the macro domain protein LRP16 represents a novel type of cofactor of NR. They also indicate that LRP16 plays an essential role in AR transactivation.

The effects of proteasome inhibitor bortezomib on a P-gp positive leukemia cell line K562/A02

The aim of this study is to clarify the efficacy of proteasome inhibitor bortezomib to multidrug resistant (MDR) acute leukemia cells. We observed the effects of bortezomib on a P-glycoprotein (P-gp) positive leukemia line K562/A02. The results showed that bortezomib has significant effects on P-gp positive K562/A02 cells including cytotoxicity (48 h IC(50): 171.36 nM), induction of apoptosis (31.71 +/- 1.07% apoptotic cells after 24 h treatment at 100 nM), and inhibition of proteasome chymotrypsin-like activity (relative activity to untreated controls: 20.07 +/- 0.66% at 24 h with 10 nM bortezomib). These effects were lower than those observed in K562 cells (IC(50), percentage of apoptotic cells, relative chymotrypsin-like activity to untreated controls were 56.28 nM, 77.95 +/- 0.35%, 5.35 +/- 2.05% after the same treatments, respectively). No synergy between daunorubicin and bortezomib was shown in the killing of K562/A02 cells (synergistic ratios were <1). P-gp expression levels did not decrease in K562/A02 cells after bortezomib treatment. Pretreatment with bortezomib does not improve the intracellular anthracycline concentration in K562/A02 cells. Bortezomib shows a promising effect for the treatment of refractory/relapsed leukemia, but it does not improve the effect of anthracycline to MDR leukemia cells.

Efficacy and safety of ginsenoside-Rd for acute ischaemic stroke: a randomized, double-blind, placebo-controlled, phase II multicenter trial

BACKGROUND AND PURPOSE

Ginsenoside-Rd is a selective competitive Ca2+ receptor antagonist. A phase II randomized, double-blind, placebo-controlled, multicenter study was conducted to examine the efficacy and safety of ginsenoside-Rd in patients with acute ischaemic stroke.

METHODS

A total of 199 patients were randomized equally to receive a 14-day infusion of placebo (group B), ginsenoside-Rd 10 mg (group A) or ginsenoside-Rd 20 mg (group C). Primary end-points were National Institutes of Health Stroke Scale (NIHSS) scores at 15 days. Secondary end-points were NIHSS scores and the Barthel Index at 8 days, the Barthel Index and the modified Rankin scale at 15 days and 90 days. The safety end-points included serious and non-serious adverse events, laboratory values and vital signs. Analysis was by intention to treat.

RESULTS

For the primary study outcome, there is significant difference amongst the three groups at 15 days in NIHSS scores (P = 0.0003). Comparing group A with B and group B with C, the difference in the mean for NIHSS was significant in statistics (P = 0.0004, P = 0.0009 respectively). This is no significant difference between group A and C (P = 0.9640). For the secondary study outcome, ginsenoside-Rd did not improve neurological functioning. Incidence of serious and non-serious adverse events was similar amongst the three groups.

CONCLUSIONS

Ginsenoside-Rd may be of some benefit in acute ischaemic stroke.

Exchange boson dynamics in cuprates: optical conductivity of HgBa_2CuO_4+delta

The electron-boson spectral density function I;{2}chi(Omega) responsible for carrier scattering of the high temperature superconductor HgBa_{2}CuO_{4+delta} (T_{c}=90 K) is calculated from new data on the optical scattering rate. A maximum entropy technique is used. Published data on HgBa_{2}Ca_{2}Cu_{3}O_{8+delta} (T_{c}=130 K) are also inverted and these new results are put in the context of other known cases. All spectra (with two notable exceptions) show a peak at an energy (Omega_{r}) proportional to the superconducting transition temperature Omega_{r} approximately 6.3k_{B}T_{c}. This charge channel relationship follows closely the magnetic resonance seen by polarized neutron scattering, Omega_{r};{neutron} approximately 5.4k_{B}T_{c}. The amplitudes of both peaks decrease strongly with increasing temperature. In some cases, the peak at Omega_{r} is weak and the spectrum can have additional maxima and a background extending up to several hundred meV.

Development of a targeted topoisomerase I inhibitor for anticancer therapy

Abstract #2146

Background:&#x2028; DNA topoisomerase I (Top1) has been identified as the molecular target of a variety of drugs, due to the important roles that they play in biological systems. Studies show that breast cancer cell lines are sensitive to Top1 agents such as camptothecin. Recent clinical trials have suggested that breast cancer patients may respond to drugs which target Top1. This suggests that some breast cancers may have elevated expression of the enzyme.&#x2028; Thus, development of Top1 inhibitors may be a good target for anticancer therapy. To better target cancer cells, the drugs can be linked to a pH-sensitive linker such as the N-Ethoxybenzylimidazoles (NEBIs) developed in our lab. The NEBIs are designed to undergo hydrolysis in slightly acidic aqueous solutions at physiological temperature, comparable to the environment found in endosomes, lysosomes, and the extracellular environment of tumors. The hydrolysis of the NEBI causes the dissociation of the drug from a carrier (e.g. Herceptin), and the rates can be tuned by modifying the electron withdrawing and donating groups on the NEBI ring. It was demonstrated that the rates can be tuned to give half-lives ranging from 36 minutes to 9 months.&#x2028; Materials and Methods:&#x2028; We have developed a new class of imidazole-containing drugs which may inhibit Top1 activity. These compounds have a 4-ring, indenoisoquinoline structure and were synthesized by a simple condensation reaction which gives good yield. Ring substituents were modified to achieve molecules of optimal potency. The resulting drugs were subsequently linked to the NEBI, and hydrolysis studies were performed to determine the rate of active drug release.&#x2028; &#x2028; Cytotoxicity of cleaved drugs was screened using the sulforhodamine B (SRB) assay and topoisomerase inhibition assays will be performed in the near future.&#x2028; Results:&#x2028; Cytotoxicity studies showed that the hydrolyzed drugs are toxic to the 10μM range in cancer cells. One of the compounds has recently been approved for the National Cancer Institute screen, in which the activity will be evalutated with 60 different cancer cell lines of diverse tumor origins. Ongoing studies will assess the topoisomerase I inhibition activity of these compounds.&#x2028; Discussion:&#x2028; We have developed a novel prodrug which comprises of a toxic Top1 inhibiting drug attached to a pH-sensitive linker. This may prove to be an effective approach to anticancer therapy. Future studies will be pursued in using folic acid as the drug carrier to target breast cancer cells. Studies show that folate receptor overexpression is associated with poor outcome in women with breast cancer. Furthermore, it has been shown that folate receptors may undergo endocytosis, which will trigger the release of the active drug from the linker.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2146.

Isolation and characterization of a highly metastatic hybrid cell line generated between estrogen receptor (ER) negative and ER positive breast cancer cells in mouse bone marrow

Abstract #2053

Background: Breast cancer cells in a patient are heterogeneous. How the presence of these heterogeneous cancer cells may contribute to cancer progression is not clear. Experimental evidence indicates that soluble factors produced by aggressive cancer cells may generate metastasis niches for less aggressive cancer cells. In this study, we sought to determine how a growing orthotopic tumor formed by an aggressive ER negative breast cancer cell line might affect the metastatic potential of a less aggressive ER positive breast cancer cell line.&#x2028; Methods and Results: Five-week-old female nude mice were injected orthotopically with metastasis-competent ER negative human breast cancer MDA-MB-231/GFP/Neo cells. After three weeks, metastasis-incompetent human breast cancer ER positive ZR-75-1/GFP/puro cells were inoculated into these mice via intra-cardiac (IC) route and puromycin resistant metastatic ZR-75-1/GFP/puro cells were flushed out of the bone marrow of one mouse and established as a variant cell line called B6. B6 cells have both estrogen-dependent and -independent cells when they were orthotopically injected into female nude mice with or without estrogen supplementation. The cells isolated from an estrogen-dependent tumor were called B6TE and the cells isolated from an estrogen-independent tumor were called B6TC. Further characterization revealed that B6TC cell was more tumorigenic without estrogen supplementation and has a unique metastatic property. More interestingly, B6TC cell was resistant to both puromycin and G418 suggesting it was derived from the fusion of MDA-MB-231/GFP/Neo and ZR-75-1/GFP/puro in the mouse bone marrow. When compared with parental MDA-MB-231/GFP/Neo, the B6TC cells were found to be more metastatic to lung and bone after IC inoculation as detected by GFP imaging, with significant development of paraplegia in the hind limbs after four weeks. More significantly, B6TC mice also developed metastases to brain, which was not observed in the MDA-MB-231/GFP/Neo group. B6TC cell has a low expression of ER alpha and CD24, and high expression of p-ERK, CD44, ALDH. It also expresses vimentin, CXCR4 and Integrin-β1. Its growth is refractory to the anti-estrogens, raloxifene and tamoxifen.&#x2028; Conclusion: Our study indicates that B6 cells generated in the bone marrow were a heterogeneous population of ER positive and ER negative cells with marked differences in their proliferative potential and malignancy. The low ER-expressing B6TC is a novel hybrid cell line generated spontaneously in a metastatic site, which has propensity to metastasize to brain in addition to lung and bone. The expression of CD44 and ALDH indicates that it has stem cell-like features. Further characterization and molecular profiling is underway to reveal the novel biomarkers. This cell line should be a useful model for the investigation of the molecular mechanism of brain metastasis and the therapeutic strategies for the treatment of metastatic breast cancer resistant to anti-estrogens.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2053.

STAT1 and STAT3 synergistically suppress EGF-induced MMP-9 activity in SKBR3 human breast cancer cell line

Abstract #2064

Background: EGF is a cytokine associated with cell proliferation, migration, and tumor invasion through EGFR activation in various cancer cells. EGFR activates its downstream molecules such as protein kinase C-δ, ERK, PI3-kinase, STAT-3. It has been shown that EGFR induces matrix metalloproteinase-9 (MMP-9), leading to invasion and migration of cancer cells. However, it has not been fully elucidated the roles of STAT-1 and STAT-3 in breast cancer cells. We investigated the regulatory mechanism of STAT-1 and STAT-3 on EGF-induced MMP-9 activity in SKBR3 cells.&#x2028; Material and Methods: EGF-induced MMP-9 activity regarding to ERK, JNK, PI-3 kinase and STAT-3 were evaluated by Western blot. Then, we transfected SKBR-3 cells with adenoviral vectors containing STAT-1 and STAT-3 to make SKBR-3 cells overexpressing each gene. We also treated SKBR-3 cells with STAT-3 siRNA. Overexpression and silencing of genes were identified with Western blot. With the treatment of EGF, MMP-9 activity was measured with gelatinase Zymography.&#x2028; Results: We confirmed that EGF increases MMP-9 activity and induces the phosphorylation of ERK, JNK, PI-3 kinase and STAT-3 in dose-dependent manner. We found that EGF-induced MMP-9 activity was significantly decreased by MEK1/2 inhibitor, UO126, and PI3-kinase inhibitor, LY294002, respectively, but not by JNK inhibitor, SP600125. In contrast to previous study, EGF-induced MMP-9 activity was inhibited by STAT-3 overexpression. We also found that it was increased by STAT-3 siRNA transfection. Moreover, we found that STAT-1 and STAT-3 co-overexpression synergistically decreased EGF-induced MMP-9 activity in STAT-1 and STAT-3 co-overexpressing SKBR-3 cells.&#x2028; Discussion: We demonstrated that EGF-induced STAT-3 activation suppresses tumor invasion through down-regulation of MMP-9 in SKBR-3 cells. Moreover, we found that there is a synergistic relationship between STAT-1 and STAT-3, inhibiting EGF-induced MMP-9 activity.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2064.

Evaluation of response to neoadjuvant chemotherapy in primary breast cancer using PET

Abstract #4019

Purpose&#x2028; To estimate the usefulness of PET scan to assess the response of neoadjuvant chemotherapy, PET scan results were compared with conventional imaging modalities(US and MRI).&#x2028; Patients and Methods&#x2028; Fourty-one patients undergoing neoadjuvant chemotherapy between December 2004 and March 2008 were included. PET scan was performed before and after chemotherapy. Pathologic results were classified into two groups; pathological complete response(pCR) and non-pCR. Clinical responses were assessed with the results of imaging modalities such as post-chemotherapy size or pSUV(postTx), size difference between treatment(delta) and reduction rate(RR) of size or pSUV, and they are compared with postoperative pathologic results.&#x2028; Results&#x2028; 7 out of 41 patients (17.1%) had pCR. The results of US shows that postTx size (1.7±1.5cm) of pCR was not dfferent from those of non-pCR (3.6±3.0cm), and the delta (3.1±1.9cm) and RR (67.7±29.1%) of pCR were higher than those of non-pCR (1.3±1.3cm, 31.0±25.4%), respectively. As a result of MRI, postTx size, delta, RR of pCR was differ from those of non-pCR (1.0±1.7cm vs 2.8±1.7cm p&lt;0.05; 4.5±1.0cm vs 2.3±1.8cm, p&lt;0.05; 88.0±20.8% vs 44.6±24.7%, p&lt;0.01). In PET scan, only postTx pSUV of pCR was differ from that of non-pCR (1.4±1.3 vs 5.3±8.3cm, p&lt;0.05). As a result of receiver operating characteristic curve analyses for the prediction of pathological response of breast cancer, area under curve values (95% confidence interval) of US, MRI, PET for delta were 0.83(0.69∼0.98), 0.91(0.80∼1.01), 0.62(0.38∼0.86), and those of RR were 0.80(0.60∼0.99), 0.90(0.77∼1.02), 0.72(0.47∼0.96), respectively&#x2028; Conclusions&#x2028; We suggest that MRI is useful method to evaluate the response of neoadjuvant chemotherapy. Although PET scan shows less effective for evaluating the response of chemotherapy than MRI, PET scan with the ability to detect the distant metastatic lesions may be helpful to decide the proper management plans for advanced breast cancer.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4019.

A fully flexible stimulator using 65 nm CMOS process for 1024-electrode epi-retinal prosthesis

This paper presents a fully flexible stimulator using 65 nm CMOS process for a 1024-electrode epi-retinal prosthesis. The stimulator can select any number of electrodes at any time and also supports both mono-polar and multi-polar stimulation. Furthermore, the stimulator supports a wide range of stimulus parameters. A novel feature is that the electrode driver operates in an alternately pull-push manner, which helps reduce headroom voltage while guaranteeing charge balance at the active electrode. The use of positive supplies instead of both positive and negative supplies simplifies CMOS circuit design. The current distribution between two nearby simultaneously active electrode groups was investigated and measurement result showed a maximum current crosstalk of 8%.

Antithrombotic therapy in children with venous thromboembolism

Antithrombotic therapy has recently become more frequent for the treatment of venous thromboembolism (VTE) in the paediatric population. This can be explained by the increased awareness of morbidities and mortalities of VTE in children, as well as the improved survival rate of children with various kinds of serious illnesses. Considering the large number of years a child is expected to survive, associated morbidities such as postthrombotic syndrome and risk of recurrence can significantly impact on the quality of life in children. Therefore, timely diagnosis, evidence-based treatment and prophylaxis strategies are critical to avoid such complications. This review summarizes the current literature about the antithrombotic treatment for VTE in infants and children. It guides the paediatric medical care provider for making a logical and justifiable decision.