Isolation of circulating tumor cells using a microvortex-generating herringbone-chip.

Rare circulating tumor cells (CTCs) present in the bloodstream of patients with cancer provide a potentially accessible source for detection, characterization, and monitoring of nonhematological cancers. We previously demonstrated the effectiveness of a microfluidic device, the CTC-Chip, in capturing these epithelial cell adhesion molecule (EpCAM)-expressing cells using antibody-coated microposts. Here, we describe a high-throughput microfluidic mixing device, the herringbone-chip, or "HB-Chip," which provides an enhanced platform for CTC isolation. The HB-Chip design applies passive mixing of blood cells through the generation of microvortices to significantly increase the number of interactions between target CTCs and the antibody-coated chip surface. Efficient cell capture was validated using defined numbers of cancer cells spiked into control blood, and clinical utility was demonstrated in specimens from patients with prostate cancer. CTCs were detected in 14 of 15 (93%) patients with metastatic disease (median = 63 CTCs/mL, mean = 386 ± 238 CTCs/mL), and the tumor-specific TMPRSS2-ERG translocation was readily identified following RNA isolation and RT-PCR analysis. The use of transparent materials allowed for imaging of the captured CTCs using standard clinical histopathological stains, in addition to immunofluorescence-conjugated antibodies. In a subset of patient samples, the low shear design of the HB-Chip revealed microclusters of CTCs, previously unappreciated tumor cell aggregates that may contribute to the hematogenous dissemination of cancer.

Expanding the limits of treatment--new strategic initiatives.

The perception that weight reduction is rarely successful is, in fact, a misperception. Between 1999-2000 and 2001-2002, there were no significant changes among adults in the prevalence of overweight, obesity, or extreme obesity, or among children aged 6 through 19 years in the prevalence of at risk for overweight. The National Heart, Lung, and Blood Institute defines successful long-term weight loss as an intentional reduction of 10% from baseline maintained for 1 year. Modest weight loss is not only beneficial but also achievable for persons with overweight and obesity. Of the Americans who have tried to lose weight, almost 50% have maintained their weight loss successfully for at least 1 year. The remaining half, those who seem unable to prevent or reverse their obesity, challenge dietetics professionals to mobilize resources, confront issues at the heart of the obesity epidemic, and develop new solutions. Work to date has paid off for millions of persons. We have stopped the epidemic of obesity. Now it is time to do more by joining health care practitioners with all other stakeholders in the effort to prevent and reverse it.

Pharmacotherapy to reduce visceral fat.

Cardiovascular disease (CVD) is the leading cause of death of men and women in the United States. The accumulation of visceral adipose tissue, as opposed to subcutaneous fat, increases the risk of developing CVD and metabolic disease. Because visceral adipose tissue uniquely contributes to the pathophysiology of CVD and insulin resistance, waist circumference is now being considered as a more useful marker of potential health risks associated with overweight and obesity than body mass index. Weight loss, particularly a reduction in waist circumference, improves insulin sensitivity, lipid profile, and serum adipocytokines, thereby reducing the risk of developing chronic disease and CVD.

Physician's guide to the new 2005 dietary guidelines: how best to counsel patients.

The Dietary Guidelines for Americans 2005 encourage most Americans to eat fewer calories, be more active, and make wiser food choices. Health care providers can influence patients' food and activity choices by providing specific counseling and presenting straightforward information.

Genotypic and histological evolution of lung cancers acquiring resistance to EGFR inhibitors.

Lung cancers harboring mutations in the epidermal growth factor receptor (EGFR) respond to EGFR tyrosine kinase inhibitors, but drug resistance invariably emerges. To elucidate mechanisms of acquired drug resistance, we performed systematic genetic and histological analyses of tumor biopsies from 37 patients with drug-resistant non-small cell lung cancers (NSCLCs) carrying EGFR mutations. All drug-resistant tumors retained their original activating EGFR mutations, and some acquired known mechanisms of resistance including the EGFR T790M mutation or MET gene amplification. Some resistant cancers showed unexpected genetic changes including EGFR amplification and mutations in the PIK3CA gene, whereas others underwent a pronounced epithelial-to-mesenchymal transition. Surprisingly, five resistant tumors (14%) transformed from NSCLC into small cell lung cancer (SCLC) and were sensitive to standard SCLC treatments. In three patients, serial biopsies revealed that genetic mechanisms of resistance were lost in the absence of the continued selective pressure of EGFR inhibitor treatment, and such cancers were sensitive to a second round of treatment with EGFR inhibitors. Collectively, these results deepen our understanding of resistance to EGFR inhibitors and underscore the importance of repeatedly assessing cancers throughout the course of the disease.

BIM expression in treatment-naive cancers predicts responsiveness to kinase inhibitors.

Cancers with specific genetic mutations are susceptible to selective kinase inhibitors. However, there is a wide spectrum of benefit among cancers harboring the same sensitizing genetic mutations. Herein, we measured apoptotic rates among cell lines sharing the same driver oncogene following treatment with the corresponding kinase inhibitor. There was a wide range of kinase inhibitor-induced apoptosis despite comparable inhibition of the target and associated downstream signaling pathways. Surprisingly, pretreatment RNA levels of the BH3-only pro-apoptotic BIM strongly predicted the capacity of EGFR, HER2, and PI3K inhibitors to induce apoptosis in EGFR-mutant, HER2-amplified, and PIK3CA-mutant cancers, respectively, but BIM levels did not predict responsiveness to standard chemotherapies. Furthermore, BIM RNA levels in EGFR-mutant lung cancer specimens predicted response and duration of clinical benefit from EGFR inhibitors. These findings suggest assessment of BIM levels in treatment-naïve tumor biopsies may indicate the degree of benefit from single-agent kinase inhibitors in multiple oncogene-addiction paradigms.