A Revolutionary Blood Test Catapults Cancer Treatment By A revolutionary blood test could advance cancer treatment with warp speed. The little device, designed by a team working at Mass General Hospital, is a 1-inch by 3-inch silicon wafer called the CTC-iChip, the first of its kind to filter out thousands of cancer cells for genetic analysis. CTC stands for "circulating tumor cells," which are found in the blood of anyone with metastatic cancer. Today, the sole Food and Drug Administration-approved CTC blood test, called CellSearch, can only roughly count cancer cells in the blood. And while counting cancer cells is helpful in determining whether a treatment is working, the CTC- iChip's new ability to extract thousands of cancer cells for mutation analysis will allow patients to have a far more tailored and less toxic treatment by targeting only those mutations that are causing the cancer. Today, this is done with drugs that block a pathway unique to a mutated cell's surface, or in the field of immunology, block the specific proteins that disguise the cancer cell from the immune system. Research over the last decade has shown that cancer types are not limited to the larger categories we usually think of — prostate, breast, colon, and so on. Nor are they limited to the various cell types within an organ, bone or muscle, such as the lining of the kidney or its base. Each cell type typically has a variety of genetic mutations. For example, non-small cell lung cancer cells have about three known mutation types or a combination of them, with each responding differently to drugs. On top of this, some of these mutations drive cancer growth, while others can be latent, making our understanding of them a key piece in designing personalized treatment. To date, most genetic analysis of tumors is done by way of a biopsy. The biopsy procedure, however, can be very difficult for a patient, especially if the tumor is in the bone, and is not possible for al