Keeping you up-to-date on recent headlines in oncology healthcare:
Selectively killing cancer stem cells ... A team of researchers has discovered a chemical that works in mice to kill the rare, but aggressive cells within breast cancers that have the ability to seed new tumors. Cancer stem cells are thought to enable cancers to spread and to reemerge after seemingly successful treatment. This new study shows that it is possible to find chemicals that selectively kill cancer stem cells. The scientists' findings appear in the current issue of Cell. "Evidence is accumulating rapidly that cancer stem cells are responsible for the aggressive powers of many tumors," said Robert Weinberg, a member of Whitehead Institute for Biomedical Research (Cambridge, Massachusetts) and one of the authors of the study. "The ability to generate such cells in the laboratory, together with the powerful techniques available at the Broad Institute (Cambridge, Massachusetts) made it possible to identify this chemical. There surely will be dozens of others with similar properties found over the next several years." Broad and Whitehead Institute researchers drew upon recent findings from Weinberg and his colleagues that suggested a way to generate in the lab large numbers of cancer cells with stem cell-like qualities. The technique works by coaxing adult cells to undergo a critical change that alters their shape and motility. At the same time, the cells adopt similar properties as stem cells. With an ample number of stem cells in hand, the Broad-Whitehead team undertook a large-scale analysis of thousands of chemical compounds, applying automated methods to search for ones with activity against breast cancer stem cells. From a pool of more than 30 promising candidates, they identified a compound with surprising potency. Compared to a common chemotherapeutic drug prescribed for breast cancer (paclitaxel), that compound dubbed salinomycin reduced the number of cancer stem cells by more than 100-fold. It also diminished breast tumor growth in mice.
FDG-PET plus CT is more effective than CT alone ... Combining these imaging techniques is a far better way to diagnose and stage colorectal liver metastases than CT alone, according to a randomized controlled trial published in this month's Journal of Nuclear Medicine. Theo Ruers, MD, from the department of surgery at Radboud University Nijmegen Medical Centre (Nijmegen, Netherlands) and colleagues reported that until now, definitive evidence that the addition of 18F-FDG PET to conventional staging leads to superior clinical results and improved clinical management in these patients has been lacking. They investigated whether the addition of 18F-FDG PET is beneficial and reduces the number of futile laparotomies. They undertook a 150-patient study whose participants had colorectal liver metastases and were recommended for surgery. The researchers randomly assigned participants to CT only (75) or CT plus 18F-FDG PET (75). They followed up with patients for at least three years. They found that the number of futile laparotomies was 45% in the control arm without 18F-FDG PET and 28% in the experimental arm with 18F-FDG PET. Ruers and his colleagues concluded the number of futile laparotomies was reduced from 45% to 28%, meaning the addition of 18F-FDG PET to the work-up for surgical resection of colorectal liver metastases prevents unnecessary surgery in one of six patients.
Group IDs biomarker that indicates risk of metastases ... It's now possible to identify head and neck cancer patients who have a higher risk of developing distant metastases or suffering a relapse, according to research by Radiation Therapy Oncology Group (RTOG; Philadelphia), who reported their findings in the Journal of Clinical Oncology. Using tumor biopsies and data from 306 patients entered on RTOG 9003, a phase III multicenter randomized trial of four radiation therapy schedules for locally advanced head and neck squamous cell carcinoma, investigators found that an increase in lysyl oxidase (LOX) expression is a predictor for the development of distant metastases, disease progression and overall survival. LOX is an enzyme associated with hypoxia, or a reduction in tissue oxygen, which is thought to increase the likelihood of disease spread. Quynh-Thu Le, MD, the study's lead author and professor in the Department of Radiation Oncology at Stanford University (Stanford, California), said "We have validated LOX as a marker for metastasis, and thereby the significance of hypoxia, in head and neck cancer patients treated with radiation therapy. We plan to continue our investigations of the prognostic abilities of LOX through future studies with patients treated with concurrent chemoradiotherapy and determine the impact of LOX in relation to human papillomavirus status, another known prognostic marker in these cancers."
Software tools improve identification of cancer biomarkers ... Personalized medicine requires that researchers discover and link biomarkers to specific disease behaviors, such as the rate of tumor progression and different responses to treatments. Two new software programs that help address the challenge have recently earned silver-level compatibility certification from the National Cancer Institute's (Bethesda, Maryland) cancer Biomedical Informatics Grid, also known as caBIG. The programs improve the process of identifying cancer biomarkers from gene expression data. Developed by May Dongmei Wang and her team in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Institute of Technology (Atlanta) and Emory University (Atlanta), the programs caCORRECT and omniBioMarker remove noise and artifacts, and identify and validate biomarkers from microarray data. "Certification by caBIG means the tools can be easily used by everyone in the cancer community to improve approaches to cancer detection, diagnosis, treatment and prevention," said Wang, an associate professor.
Quantum dots used in test to find early signs of cancer ... Using tiny crystals called quantum dots, Johns Hopkins University (Baltimore) researchers have developed a highly sensitive test to look for DNA attachments that often are early warning signs of cancer. The test, which detects both the presence and the quantity of certain DNA changes, could alert people who are at risk of developing the disease and could tell doctors how well a particular cancer treatment is working. The new test was reported in the current issue of Genome Research. "If it leads to early detection of cancer, this test could have huge clinical implications," said Jeff Tza-Huei Wang, an associate professor of mechanical engineering whose lab team played a leading role in developing the technique. "Doctors usually have the greatest success in fighting cancer if they can treat it in its early stage." The study, which included the detection of DNA markers in sputum from lung cancer patients, was designed to show that the technology was sound. Compared to current methods, the test appeared to be more sensitive and delivered results more quickly, the researchers said. The target of the test is a biochemical change called DNA methylation, which occurs when a chemical group called methyl attaches itself to cytosine, one of the four nucleotides or base building blocks of DNA. When methylation occurs at critical gene locations, it can halt the release of proteins that suppress tumors. When this occurs, it is easier for cancer cells to form and multiply. As a result, a person whose DNA has this abnormal gene DNA methylation may have a higher risk of developing cancer. The methylation changes also appear to be an early event that precedes the appearance of genetic mutations another precursor to cancer.
— Compiled by Lynn Yoffee, MDD