From the Lab: Biotechnology

Test for Cancer Cells in Blood
An inexpensive microfluidic chip could lead to earlier cancer detection and treatment.

Source: “Isolation of rare cultivating tumour cells in cancer patients by microchip technology”
Mehmet Toner et al.
Nature 450: 1235-1239

Results: A microfluidic device designed by researchers at Massachusetts General Hospital in Boston can detect very low blood levels of cells from malignant tumors. In initial tests, the low-cost device detected such cells in the blood of all but one of 116 patients with various types of cancer.

Why it matters: A malignant tumor continually sheds cells into the bloodstream, spreading cancer to other tissues. Changes in the number of circulating cancer cells indicate changes in the size of the tumor during treatment. A cheap way to detect and monitor those cancer cells could allow doctors to regularly assess the effectiveness of treatment, as they do by measuring levels of viral RNA in HIV patients. Researchers can also examine cells captured on the microfluidic chip for molecular markers that suggest a more aggressive form of cancer or a type of tumor that will respond to specific drugs.

Methods: The device consists of a business-card-size silicon chip dotted with 80,000 microscopic posts. Each post is coated with a molecule that binds to a specific protein found on most cells originating from solid tumors, such as those found in breast, lung, and prostate cancer. As blood flows through small channels in the chip, tumor cells stick to the posts.

Next steps: Larger clinical trials involving patients with lung and prostate cancer will help determine how best to use the chip.

Source: “Treatment of sickle cell anemia mouse model with IPS cells generated from autologous skin”
Tim M. Townes, Rudolf Jaenisch, et al.
Science 318: 1920-1923, published online December 6, 2007

Results: Scientists have cured a blood disease in mice using cells from the animals’ tails. A new technique that does not require the use of embryos enabled the researchers to reprogram the cells to behave like embryonic stem cells.

Why it matters: The findings are the first to demonstrate the potential of such cells, known as induced pluripotent cells, in treating disease. The cells have been the source of great excitement among both researchers and the public because they hold therapeutic promise and because they sidestep the major ethical concern associated with embryonic stem cells: the destruction of embryos.

Methods: Rudolf Jaenisch and his colleagues at the Whitehead Institute for Biomedical Research in Cambridge, MA, reprogrammed the mouse tail cells to express four genes that are normally active only during embryonic development. After correcting the genetic defect responsible for sickle-cell anemia, they treated the cells with growth factors to trigger the development of blood-­forming stem cells. Mere days after the researchers injected the stem cells into the animals’ bone marrow, symptoms of the disease had reversed.

Next steps: Scientists are concerned that the mechanism used to reprogram the cells to make them pluripotent could increase the risk of cancer. To make the cells safe for human use, the researchers are developing alternative methods.