Monday, January 3, 2011

The Cancer Chip

There was a Press Release today covered in Technology Review regarding the chip which will catch cancer cells in the blood. The Tech Review states:

The prototype, developed by Mehmet Toner and collaborators at MGH, consists of a business-card-size silicon chip dotted with tens of thousands of microscopic posts. Each post is coated with a molecule that binds to a protein unique to cells from a specific type of tumor, such as breast, lung, or prostate cancer. As blood flows through the chip, tumor cells stick to the posts. In 2007, the researchers first showed that the chip could capture these rare cells--which make up just one in a billion cells in blood--in high enough numbers to analyze them for molecular markers.

The ultimate goal is to use the device to tailor cancer treatments to individual patients by monitoring cancer cell counts and by identifying the molecular attributes of an individual's cancer. For example, specific markers can highlight a more aggressive form of cancer or a tumor that will respond to specific cancer drugs, while genetic changes in the tumor might signal the need to change treatments. MGH and four other research institutions, have already received a $15 million grant from the organization Stand Up to Cancer to test the prototype. But that technology is expensive and complicated to use, with each chip costing about $500, according to the Boston Globe.

There are however some concerns:

1. By the time the cancer cells are freely circulating they may most likely have metastasized. Take a prostate cancer, PCa, which may be Gleason 5 to 7, and it is most likely still encapsulated. It must generally get to an 8-10 to met. At that point there are PCa cells circulating. If so, what is the benefit, because the PSA most likely is well over 10.

2. There is the conundrum of the stem cell theory of cancer, namely that there are stem cells and these are the cells which will spread the cancer. Can we distinguish stem cells from plain old cancer cells. Not yet clear we can do it if we have them, no less looking in the blood stream.

3. A cell which may be cancerous, say morphologically with large nucleoli and other markers must be examined in more detail. Say PCa, can we see if it has no PTEN, what of mTOR, c-myc, and the list of other genes, and what of the miRNAs which we may now suspect to be markers as well. We have to look at a single cell. May be tough, since it is already tough in a path study.

Not that this is not a good idea, but the Press seems to have said more than is there. Shame, since if it does not deliver to the level expected that in itself is negative. Nano technology has greater potential possibly, since with it we can send them through organs with surface collectors and look for the cell markers.