B Yang

NexFET generation 2, new way to power

In this paper, an integrated NexFET power module is presented to meet requirements on next-generation, high efficiency and high current density DC-DC converters for computer applications. The new power module uses an innovative stacked-die package technology, implements low Vth power MOSFET in the low-side position, and introduces monolithically integrated components to avoid shoot-through and minimize voltage ringing at the switch node. In synchronous buck application, this power module achieves over 90% efficiency and low switch node ringing at high output current rating (25A) and high operation frequency (1MHz) under 12V input and 1.3V output condition.

Advanced Low-Voltage Power MOSFET Technology for Power Supply in Package Applications

In this paper, a high-current dc-dc power supply in package is reported with an emphasis on the design aspects of the low- and high-side power MOSFETs embedded in the power module. A new NexFET structure with its source electrode on the bottom side of the die (source down) is designed to enable an innovative stacked-die PSiP technology with significantly reduced parasitic inductance and package footprint. A gate voltage pulldown circuitry monolithically integrated in the low-side NexFET is introduced to effectively prevent shoot-through faults even when a very low gate threshold voltage is used to reduce conduction and body diode reverse-recovery-related power losses. In addition, an asymmetric gate resistor circuitry is monolithically integrated in the high-side NexFET to minimize voltage ringing at the switch node. With all these novel device technology improvements, the new power supply in package module delivers a significant improvement in efficiency and offers an excellent solution for future high-frequency, high-current-density dc-dc converters.

Design considerations on low voltage synchronous power MOSFETs with monolithically integrated gate voltage pull-down circuitry

In this paper, a monolithically integrated gate voltage pull-down circuitry is presented to avoid the unintentional C·dV/dt induced turn-on. The concept of a low threshold voltage MOSFET with this integrated gate voltage pull-down circuitry is introduced as a contributing factor to the next generation high frequency DC-DC converter efficiency improvement. Design considerations on this new device and influences of critical design parameters on device/circuit performance will be fully discussed. In synchronous buck application, this integrated power module achieves more than 2% efficiency improvement over reference solution at high operation frequency (1MHz) under 19V input and 1.3V output condition.

Abstract P3-02-01: Pre-operative breast MRI would not benefit breast cancer patients' survival, even in young patients treated with breast-conservative surgery

Background Although breast magnetic resonance imaging (MRI) could help to identify occult lesions in breast cancer, its role in patient outcome has always been controversial. The current study aimed to evaluate the role of MRI in Asian breast cancer patients, especially young patients that might have dense breasts. Methods Patients with non-metastatic unilateral breast cancer who received surgery in our institute during 2007-2013 were retrospectively reviewed. The differences between groups were compared using Pearson9s χ2 test.Loco-regional recurrence-free survival (LRRFS) and recurrence-free survival (RFS) were estimated using the Kaplan-Meier method. Results A total of 13,681 patients were included into analysis, among which 5823 (42.6%) had pre-operative MRI. Of all patients, 39.7% were stage 0-I according to TNM system, 35.5% were stage II, 14.8% were stage III and 10.0% could not be staged. Patients with axillary lymph node metastasis were comparable in MRI and non-MRI groups (35.3% versus 35.6%, P=0.695). The percentile of patients receiving MRI increased from 7.3% in 2007 to 67.5% in 2013. Patients in the breast-conservative surgery (BCS) group were more likely to receive MRI compared with the mastectomy group (P Age and menopausal status were also related with the choice of pre-operative MRI. When patients were grouped according to age, 56.7%, 48.9%, 43.6%, 37.0% and 27.1% patients in the ≤35, 36-45, 46-55, 56-65 and >65 years old group had MRI, respectively (P In survival analysis, the average follow-up time for the MRI group (N=5823) and non MRI group (N=7858) were 88.5 and 114.4 months, during which 238 (4.1%) and 464 (5.9%) breast cancer recurrences occurred, while 63 (1.1%) and 159 (2.0%) loco-reginal recurrences occurred. The estimated 5-year RFS for MRI group and non-MRI group were 90.1% and 90.0% (P=0.510). The 5-year LRR-free survival LRRFS for MRI group and non-MRI group were 96.7% and 97.3% (P=0.128). In subgroup analysis, 2376 patients received BCS, and 11,035 received mastectomy. Patient in the pre-operative MRI group did not have superior RFS or LRRFS compared with the non-MRI group, regardless of surgical management (BCS versus mastectomy). Then we restrained the analysis to patients who were ≤45 years old and treated with BCS. A total of 699 patients had pre-operative MRI, and 419 patients did not. The 5-year RFS for MRI group and non-MRI group were 95.8% versus 94.6% (P=0.231); the 5-year LRRFS for MRI group and non-MRI group were 99.8% and 97.1% (P=0.144). Conclusions There was an increasing trend of pre-operative MRI examination during 2007-2013, especially in young patients and patients treated with BCS. However, pre-operative MRI could not benefit breast cancer patients9 survival by detecting occult lesions, even in young patients treated with BCS, who were considered to have dense breasts. Citation Format: Huang N, Chen J, Yang B, Quan C, Xue J, Huang X, Wu J. Pre-operative breast MRI would not benefit breast cancer patients9 survival, even in young patients treated with breast-conservative surgery [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-02-01.

Abstract P2-03-08: miR-621 suppresses the metastatic cascade in breast cancer patients

Purpose: In previous study, we had shown that miR-621 could sensitize breast cancer to chemotherapy by suppressing FBXO11 and enhancing p53 activity. In this study, we aimed to define miR-621 prognosis value in breast cancer patients, and to explore the potential molecular mechanisms. Experimental Design: 70 patients with stages II and III breast cancer were included as validation set. The correlation between miR-621 expression level and prognosis in breast cancer patients was confirmed. In parallel, in vitro and in vivo analyses were carried out to determine the potential mechanisms of miRNA-dependent prognosis. Results: We validated that lower than higher miR-621 expression level was markedly associated with poor metastasis-free survival in breast cancer patients(P=0.03). In breast cancer cell lines, ectopic overexpression of miR-621 inhibited proliferation, migration, invasion, and metastasis both in vitro and in vivo. The potential miR-621-target genes were determined by TargetScan and miRNA CLIP-seq database. Among those, PAK7 was verified as one of the direct targets of miR-621 in breast cancer cells, whose expression level positively associated with recurrence and metastasis in breast cancer patients. The molecular mechanisms by which miR-621/PAK7 axis regulates recurrence and metastasis may involve regulation of epithelial-mesenchymal transition (EMT) in breast cancer cells. Conclusions: Our study revealed a strong correlation between miR-621 expression and metastasis in breast cancers. High level of miR-621 was negatively associated with poor metastasis-free survival. The increased metastasis-free survival may be mediated by down-regulation of PAK7 gene, which leads to reduced EMT in breast cancer cells. Therefore, miR-621 may represent a therapeutic target for early metastasis breast cancer. Citation Format: Xue J, Chi Y, Chen J, Yang B, Wu J. miR-621 suppresses the metastatic cascade in breast cancer patients. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-03-08.

Abstract P2-19-07: Current trends of breast reconstruction after mastectomy for breast cancer patients in China

Background: To ascertain the current trends of breast reconstruction (BR) for breast cancer patients in China, we conducted a retrospective study in Committee of Breast Cancer Society, Chinese Anti-Cancer Association. Methods: We designed a questionnaire for this study, and it included questions on surgeon demographics, number of mastectomy and BR, type and timing of BR, reconstructive choices in the setting of preoperative or postoperative radiotherapy (RT) or chemotherapy, complication, oncoplastic surgery, fat grafting, physician and patient satisfaction, etc. All data were collected until 2012. Questionnaires were sent to 52 members of Committee of Breast Cancer Society by e-mail. By Jun-2013, 30 questionnaires (response rate 57.7%) had been returned. Among all, 3 were excluded for not performing BR. Finally, 27 respondents were included. Results: All but one of these 27 hospitals were Class Three Grade A hospitals in China. A total of 402 surgeons worked in the general surgery or oncological surgery department, among them, only 84 (20.9%) were able to perform BR. Surgeons from 10 hospitals would also choose to cooperate with the plastic department to finish the complicated reconstructive procedure. In 2012, 21026 mastectomies were performed; among them, 679 (3.2%) received immediate BR, 102 (0.5%) received delayed BR while 192 (0.9%) received delayed-immediate one. At the same time, 414 (2.0%) had their breast reconstructed by implant while 393 (1.9%) chose the autologous ones, the choices of reconstructive type were not recorded for other 166 (0.8%) cases. According to these 27 respondents, 88.9% predominantly performed prosthetic (1265 cases in all) or latissimus dorsi myocutaneous flap (LDMF) with or without an implant (1571 cases in all) BR from the time of their first BR operation to the end of 2012. During the same period, 327 pedicled transverse rectus abdominis myocutaneous (TRAM) BR were performed in 20 hospitals, while 169 free TRAM BR, which requiring technique of microsurgery, were carried out in 9 hospitals (68.6% were performed by a single surgeon from Nov-2006). The overall complication rate of BR was 12.4%. As RT had low to medium effect on increasing the operational difficulties and influencing the esthetic outcomes of BR, about 75% surgeons would choose delayed autologous BR in patients who had previous RT. Autologous flaps were also recommended for patients who need postoperative RT, but the timing still remained controversial. The overall cosmetic outcomes of the reconstructed breasts satisfied the majority of physicians and patients. Conclusion: With the growing number of breast cancer patients who need to undergo mastectomy, more and more BR are needed to improve the quality of life for them, but the ratio is still low in China, partially because of the lack of qualified plastic surgeons. As free flap BR requiring microsurgical techniques seems still complicated for most surgeons, implant and LDMF BR are the most common choices for patients nowadays in China. In addition, the effect of radiotherapy will be an important consideration when deciding the type and timing of BR. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-19-07.

Abstract P1-01-13: Intraoperative evaluation of sentinel lymph nodes using touch imprint cytology in patients with early-stage breast cancer: A series of 4367 procedures

Background: As the screening for breast cancer becomes common in China, an increasing number of early-stage breast cancer has been detected. For those patients, especially the ones with cliniaclly negetive lymph nodes, sentinel lymph node biopsy (SLNB) plays an important role in the assessment of the axillary status, while minimizing the mobidity of axillary lymph node dissection(ALND). Accurate intraoperative assessment of SLN metastases enables the selection of patients for ALND during the same operation. Touch imprint cytology (TIC) serves as a main intraoperative evaluation of SLNs in our institute since Feb-2005. The purpose of this study is to evaluate its clinical value. Methods: Early-stage breast cancer patients treated in our institute between Feb-2005 and Apr-2013 enrolled in this study. To avoid breast tissue contamination, all patients had an intraoperative SLNB performed before undergoing lumpectomy or mastectomy. The fresh SLNs were sectioned into 1.5-3.0mm pieces along the short axis, TIC was performed on both surfaces of each piece, its result was correlated with the histological assessments with Hematoxylin-Eosin (HE73(24 Suppl): Abstract nr P1-01-13.

Abstract P1-01-20: Validation of MSKCC Nomogram in Predicting Sentinel Lymph Node Metastasis of a Chinese Breast Cancer Population

Background: The Memorial Sloan-Kettering Cancer Center (MSKCC) developed a nomogram to predict the presence of sentinel lymph node (SLN) metastasis in breast cancer patients. Our study was designed to validate the clinical value of the MSKCC nomogram in Chinese early-stage breast cancer population. Methods: Data were collected from 524 patients with successful SLN biopsy who were treated during 2005 March to 2009 October. Positive SLN metastasis was found in 154 patients. Touch imprint cytology (TIC) and serial section with HE70(24 Suppl):Abstract nr P1-01-20.

Abstract P1-01-07: Touch Imprint Cytology for Intraoperative Evaluation of Sentinel Lymph Node in Patients with Early-Stage Breast Cancer: A Five-Year Experience

Background: Accurate intraoperative diagnosis of sentinel lymph node (SLN) metastases enables the selection of patients for axillary lymph node dissection during the same operation and reduces the need for re-operation. Touch imprint cytology (TIC) serves as a main intraoperative assessment of SLNs in our institute for over five years. The purpose of the present study is to evaluate the clinical value of TIC as an intraoperative assessment for the diagnosis of SLN. Methods: Patients treated for early-stage breast cancer between Feb-2005 and May-2010 enrolled in the study. TIC was routinely performed intraoperatively, the result of which was correlated with definitive histological assessments of serial section with Hematoxylin-Eosin staining. Subsequent immunohistochemistry staining with CK-19 and MUC-1 were performed for research purposes. The Memorial Sloan-Kettering Cancer Center (MSKCC) nomogram was applied in this retrospective study to estimate probability of SLN involvement of each case. Results: A total of 1,077 patients with early-stage breast cancer enrolled in the study, and 3,048 SLNs were successfully harvested during the surgeries. Among those, 265 (24.6%) patients proved to have at least one SLN that was positive for carcinoma. Altogether, 397 (13.0%) involved nodes were removed from patients in the aforementioned patient pool. Based on the final pathology report, the sensitivity, specificity and overall accuracy of TIC was 83.4%, 99.0% and 95.2%, respectively on a per patient basis, and 78.3%, 99.4% and 96.7%, respectively on a per node basis. The sensitivity for macrometastasis and micrometastasis are 88.6% and 39.3%, respectively on a per patient basis, while 87.4% and 31. 3%, respectively on a per node basis. Of the patients included in this study, 98.7% had a positive SLN within their first three harvested SLNs. All the patients who were at a Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-01-07.