Dynamic and subtype-specific interactions between tumour burden and prognosis in breast cancer.

We investigated the relationship between the prognostic importance of anatomic tumour burden and subtypes of breast cancer using data from the Korean Breast Cancer Registry Database. In HR+/HER2+ and HR-/HER2-tumours, an increase in T stage profoundly increased the hazard of death, while the presence of lymph node metastasis was more important in HR+/HER2+ and HR-/HER2+ tumours among 131,178 patients with stage I-III breast cancer. The patterns of increasing mortality risk and tumour growth (per centimetre) and metastatic nodes (per node) were examined in 67,038 patients with a tumour diameter ≤ 7 cm and < 8 metastatic nodes. HR+/HER2- and HR-/HER2- tumours showed a persistent increase in mortality risk with an increase in tumour diameter, while the effect was modest in HER2+ tumours. Conversely, an increased number of metastatic nodes was accompanied by a persistently increased risk in HR-/HER2+ tumours, while the effect was minimal for HR-/HER2- tumours with > 3 or 4 nodes. The interactions between the prognostic significance of anatomic tumour burden and subtypes were significant. The prognostic relevance of the anatomic tumour burden was non-linear and highly dependent on the subtypes of breast cancer.

Electron beam induced removal of PMMA layer used for graphene transfer.

We demonstrate the development of an effective technique to remove the poly methyl methacrylate (PMMA) layer used for transferring graphene synthesized by a chemical vapor deposition (CVD). This was achieved utilizing electron-beam bombardment and following developing processes, prior to the use of conventional organic solvents. Field-effect transistors were fabricated on the transferred graphene in order to explore their Dirac points and carrier motilities in the ambient condition - the results were then compared with those from the conventional wet chemical treatment. It was found that the Dirac points were located close to the zero gate bias when compared to those from the acetone and the acetic acid treatments. Most significantly, the field-effect mobility reached as high as 6770 cm2/Vs and 7350 cm2/Vs on average for holes and electrons, respectively, which is more than seven times improvement in comparison to conventional acetone treatments for CVD-grown graphene devices.

Long-term Survival Outcomes of Primary Breast Cancer in Women With or Without Preoperative Magnetic Resonance Imaging: A Matched Cohort Study.

AIMS: To investigate whether preoperative magnetic resonance imaging (MRI) in patients with primary breast cancer is predictive of disease-free (DFS) and overall survival and to determine the prognostic factors indicating survival. MATERIALS AND METHODS: This retrospective study was approved by the institutional review board and the requirement for informed consent was waived. From 2009 to 2010, 828 women with primary breast cancer and preoperative MRI were matched with 1613 women without such imaging. Patients were matched with regards to 25 patient and tumour-related covariates. A Cox proportional hazards model was used to investigate the time to recurrence and to estimate the hazard ratio for preoperative MRI. Log-rank tests and Cox proportional hazards survival analysis were carried out on total recurrence DFS and overall survival in the unmatched datasets. RESULTS: In total, 799 matched pairs were available for survival analysis. The MRI group showed a tendency towards better survival outcome; however, there were no significant differences in DFS and overall survival. Age at diagnosis (DFS hazard ratio = 0.98; overall survival hazard ratio = 1.04), larger tumour size (DFS hazard ratio = 1.01; overall survival hazard ratio = 1.02), triple negative breast cancer (DFS hazard ratio = 2.64; overall survival hazard ratio = 3.44) and the presence of lymphovascular invasion (DFS hazard ratio = 2.12; overall survival hazard ratio = 2.70) were independent significant variables for worse DFS and overall survival. CONCLUSION: Preoperative MRI did not result in an improvement in a patient's outcome. Age at diagnosis, tumour size, molecular subtype and lymphovascular invasion were significant independent factors affecting both DFS and overall survival.

Suspended single-walled carbon nanotube fluidic sensors.

In this paper, we demonstrate the fabrication of liquid flow sensors employing partially suspended single-walled carbon nanotubes (SWNTs). We have found that the sign of the conductance change in SWNT flow sensors is not influenced by the direction of water flow for both supported and suspended devices. Therefore, the streaming potential is not the principal mechanism of the SWNT sensor response. Instead, the conductance change is more likely due to a reduction in the cation density in the electrical double layer, whose equilibrium conditions are determined by the liquid flow rate. More importantly, we have found that the sensitivity of suspended SWNT devices is more than 10 times greater than that of supported SWNT devices. A reduced screening effect and an increase in effective sensing volume are responsible for the enhanced sensitivity, which is consistent with the ion depletion model. We also have measured conductance as a function of gate bias at different flow rates and have determined the flow-rate dependent effective charge density, which influences the electrostatic configuration around SWNT devices.

Sensitive detection of yeast using terahertz slot antennas.

We demonstrated sensitive detection of individual yeast cells and yeast films by using slot antenna arrays operating in the terahertz frequency range. Microorganisms located at the slot area cause a shift in the resonant frequency of the THz transmission. The shift was investigated as a function of the surface number density for a set of devices fabricated on different substrates. In particular, sensors fabricated on a substrate with relatively low permittivity demonstrate higher sensitivity. The frequency shift decreases with increasing slot antenna width for a fixed coverage of yeast film, indicating a field enhancement effect. Furthermore, the vertical range of the effective sensing volume has been studied by varying the thickness of the yeast film. The resonant frequency shift saturates at 3.5 µm for a slot width of 2 µm. In addition, the results of finite-difference time-domain simulations are in good agreement with our experimental data.

Terahertz conductivity of reduced graphene oxide films.

We performed time-domain terahertz (THz) spectroscopy on reduced graphene oxide (rGO) network films coated on quartz substrates from dispersion solutions by spraying method. The rGO network films demonstrate high conductivity of about 900 S/cm in the THz frequency range after a high temperature reduction process. The frequency-dependent conductivities and the refractive indexes of the rGO films have been obtained and analyzed with respect to the Drude free-electron model, which is characterized by large scattering rate. Finally, we demonstrate that the THz conductivities can be manipulated by controlling the reduction process, which correlates well with the DC conductivity above the percolation limit.

Diffusion Length in Nanoporous Photoelectrodes of Dye-Sensitized Solar Cells under Operating Conditions Measured by Photocurrent Microscopy.

We determined the carrier diffusion lengths in nanoporous layers of dye-sensitized solar cells by using scanning photocurrent microscopy. The diffusion lengths were found to be 60-100 µm for the conventional cells. In addition, we found a correlation between the carrier diffusion lengths and the cell efficiency, which proved that improvement in the diffusion length is one of the crucial factors for optimizing device performance. The diffusion length was measured for various operating conditions by varying parameters such as solar light intensity and applied electrical voltage. In particular, we observed electric-field-driven, carrier transport phenomena (i.e., drift current) in modified cells. Fitting with the drift-diffusion model enabled us to extract the electric field strengths present in the TiO2 nanoporous layer.

Comparison of mammography, sonography, MRI and clinical examination in patients with locally advanced or inflammatory breast cancer who underwent neoadjuvant chemotherapy.

OBJECTIVES: The purpose of this study was to determine the relative accuracies of mammography, sonography, MRI and clinical examination in predicting residual tumour size and pathological response after neoadjuvant chemotherapy for locally advanced or inflammatory breast cancer. Each prediction method was compared with the gold standard of surgical pathology. METHODS: 43 patients (age range, 25-62 years; mean age, 42.7 years) with locally advanced or inflammatory breast cancer who had been treated by neoadjuvant chemotherapy were enrolled prospectively. We compared the predicted residual tumour size and the predicted response on imaging and clinical examination with residual tumour size and response on pathology. Statistical analysis was performed using weighted kappa statistics and intraclass correlation coefficients (ICC). RESULTS: The ICC values between predicted tumour size and pathologically determined tumour size were 0.65 for clinical examination, 0.69 for mammography, 0.78 for sonography and 0.97 for MRI. Agreement between the response predictions at mid-treatment and the responses measured by pathology had kappa values of 0.28 for clinical examination, 0.32 for mammography, 0.46 for sonography and 0.68 for MRI. Agreement between the final response predictions and the responses measured by pathology had kappa values of 0.43 for clinical examination, 0.44 for mammography, 0.50 for sonography and 0.82 for MRI. CONCLUSION: Predictions of response and residual tumour size made on MRI were better correlated with the assessments of response and residual tumour size made upon pathology than were predictions made on the basis of clinical examination, mammography or sonography. Thus, the evaluation of predicted response using MRI could provide a relatively sensitive early assessment of chemotherapy efficacy.

Correlation between mammographic and sonographic findings and prognostic factors in patients with node-negative invasive breast cancer.

OBJECTIVES: The purpose of this study was to correlate sonographic and mammographic findings with prognostic factors in patients with node-negative invasive breast cancer. METHODS: Sonographic and mammographic findings in 710 consecutive patients (age range 21-81 years; mean age 49 years) with 715 node-negative invasive breast cancers were retrospectively evaluated. Pathology reports relating to tumour size, histological grade, lymphovascular invasion (LVI), extensive intraductal component (EIC), oestrogen receptor (ER) status and HER-2/neu status were reviewed and correlated with the imaging findings. Statistical analysis was performed using logistic regression analysis and intraclass correlation coefficient (ICC). RESULTS: On mammography, non-spiculated masses with calcifications were associated with all poor prognostic factors: high histological grade, positive LVI, EIC, HER-2/neu status and negative ER. Other lesions were associated with none of these poor prognostic factors. Hyperdense masses on mammography, the presence of mixed echogenicity, posterior enhancement, calcifications in-or-out of masses and diffusely increased vascularity on sonography were associated with high histological grade and negative ER. Associated calcifications on both mammograms and sonograms were correlated with EIC and HER-2/neu overexpression. The ICC value for the disease extent was 0.60 on mammography and 0.70 on sonography. CONCLUSION: Several sonographic and mammographic features can have a prognostic value in the subsequent treatment of patients with node-negative invasive breast cancer. Radiologists should pay more attention to masses that are associated with calcifications because on both mammography and sonography associated calcifications were predictors of positive EIC and HER-2/neu overexpression.

Short term results from GHRH analogue use in pre-menopausal breast cancer in Korea.

BACKGROUND: Hormone receptor-positive, pre-menopausal breast cancer patients can be treated by chemotherapy and/or ovarian suppression therapy. We reported our experience of gonadotropin-releasing hormone analogue plus tamoxifen (GnRHa+T) or adriamycin and cyclophosphamide (AC) followed by tamoxifen (AC-->T) in pre-menopausal women with hormone-response, node-negative breast cancer. METHODS: We retrospectively reviewed the records of 587 pre-menopausal women with hormone-responsive, node-negative breast cancer. Of these, 269 were treated with adriamycin and cyclophosphamide (AC) followed by tamoxifen (AC-->T), and 318 were treated with gonadotropin-releasing hormone analogue plus tamoxifen (GnRHa+T). Among them, 151 patients were treated by goserelin acetate 3.6 mg/kg and 125 patients were treated by leuprorelin acetate 3.75 mg/kg every 28 days subcutaneously. FINDINGS: At a median follow-up time of 30 months, eight patients had relapsed and three had died. DFS did not differ between the AC-->T and GnRHa+T groups. Of the three deaths, two were not related to breast cancer. The third patient, in the AC-->T group, died because of brain metastasis. GnRHa+T treatment had no effect on blood profile and did not cause the development of detrimental symptoms but decreased bone mineral density. The efficacy of leuprorelin was similar to that of goserelin. INTERPRETATION: GnRHa+T treatment can be an alternative treatment option in pre-menopausal women with endocrine-responsive, node-negative, breast cancer patients. The efficacy and tolerability of leuprorelin were similar to that of goserelin.

Tissue microarray-based study of patients with lymph node-negative breast cancer shows that HER2/neu overexpression is an important predictive marker of poor prognosis.

BACKGROUND: Despite good prognosis in most cases of lymph node (LN)-negative breast cancer, individual patients may have markedly different clinical outcomes. Here, we investigated the prognostic significance of HER2/neu overexpression in these tumors. MATERIALS AND METHODS: We employed a tissue microarray to examine HER2/neu overexpression by immunohistochemical staining in 359 consecutive patients diagnosed with LN-negative breast cancer, who underwent surgery from January 1993 to December 1998. RESULTS: HER2/neu overexpression was detected in 81 of 359 (23.1%) patients. The 10-year disease-free survival (DFS) values (81.2% versus 61.8%, P value 0.000) and overall survival (OS) rates (85.7% versus 63.9%, P value 0.000) were significantly different between cases with HER2/neu-negative or HER2/neu-positive tumors. After multivariate analysis, HER2/neu status and tumor size were identified as independent prognostic factors for 10-year OS. Moreover, HER2/neu overexpression was significantly associated with poorer clinical outcomes in an intermediate-risk group identified by the St Gallen classification (10-year DFS, 79.6% versus 61.8%, P value 0.000; 10-year OS, 84.7% versus 63.9%, P value 0.000). CONCLUSIONS: Our results show that HER2/neu overexpression is an important independent prognostic factor for LN-negative breast cancer cases and support the theory that more intensive adjuvant chemotherapy is required in the population with HER2/neu overexpression.

A single well push-pull test method for in situ determination of denitrification rates in a nitrate-contaminated groundwater aquifer.

In this study a single-well, "push- pull" test method is adapted for determination of in situ denitrification rates in groundwater aquifers. The rates of stepwise reduction of nitrate to nitrite, nitrous oxide, and molecular nitrogen were determined by performing a series of push-pull tests. The method consists of the controlled injection of a prepared test solution ("push") into an aquifer followed by the extraction of the test solution/ground water mixture ("pull") from the same location. The injected test solution consists of ground water containing a nonreactive tracer and one or more biologically reactive solutes. Reaction rate coefficients are computed from the mass of reactant consumed and/or product formed. A single Transport Test, one Biostimulation Test, and four Activity Tests were conducted for this study. Transport tests are conducted to evaluate the mobility of solutes used in subsequent tests. These included bromide (a conservative tracer), fumarate (a carbon and/or source), and nitrate (an electron acceptor). Extraction phase breakthrough curves for all solutes were similar, indicating apparent conservative transport of the solutes prior to biostimulation. Biostimulation tests were conducted to stimulate the activity of indigenous heterotrophic denitrifying microorganisms and consisted of injection of site ground water containing fumarate and nitrate. Biostimulation was detected by the simultaneous production of carbon dioxide and nitrite after each injection. Activity tests were conducted to quantify rates of nitrate, nitrite, and nitrous oxide reduction. Estimated zero-order degradation rates decreased in the order nitrate > nitrite > nitrous oxide. The series of push-pull tests developed and field tested in this study should prove useful for conducting rapid, low-cost feasibility assessments for in situ denitrification in nitrate-contaminated aquifers.

Prognostic values of KAI1 and survivin expression in an infiltrating ductal carcinoma of the breast.

AIMS: To investigate KAI1 and survivin expression in infiltrating ductal carcinomas, and to evaluate the relationship between clinicopathological factors and KAI1 and survivin expression levels in breast cancers. METHODS AND RESULTS: KAI and survivin expression levels were measured in 62 patients, using immunohistochemical staining. Western blot analysis was performed on eight frozen cases. DNA ploidy was determined by flow cytometry. The results of the KAI1 expression analyses were as follows: in 14 cases (22.6%) levels were preserved (++), in 30 cases (48.4%) levels were reduced (+), in 18 cases (29.0%) no KAI1 expression was detected, so these were designated 'lost' (-). Results of assessments of survivin expression were as follows: six cases (9.7%) were strong positive (++), 28 cases (45.15%) were positive (+), and 28 cases (45.15%) were negative. Survivin (p=0.0009) and KAI1 (p=0.0091) expression levels were directly correlated with survival rate. However, no significant difference was determined to exist between survivin and KAI1 expression levels and the clinicopathological factors. DNA ploidy did not correlate with survivin and KAI1 expression levels and survival rate. Four different groups, according to their survivin and KAI1 expression levels, correlated with the clinical stage and survival rate. CONCLUSION: KAI1 and survivin expression levels might be prognostic factors in breast cancers.