FDA Clears Test that Helps Identify Type of Cancer in Tumor Sample

The U.S. Food and Drug Administration has cleared for marketing a test that can help health care professionals determine what type of cancer cells are present in a malignant tumor.

The Pathwork Tissue of Origin test compares the genetic material of a patient’s tumor with genetic information on malignant tumor types stored in a database.

It uses a microarray technology to analyze thousands of pieces of genetic material at one time. The test considers 15 common malignant tumor types, including bladder, breast, and colorectal tumors.

"The clearance of the Pathwork test is another step in the continued integration of molecular-based medicine into standard practice," said Daniel Schultz, M.D., director of the FDA's Center for Devices and Radiological Health, which oversees medical diagnostics. "In the past, scientists have classified different types of cancers based on the organs in which the tumors develop. With the help of microarray technology, they will be able to classify these types of cancers in a standardized non-reader dependent manner based on the patterns of gene activity in the tumor cells."

The Pathwork Tissue of Origin test is the second in vitro diagnostic multivariate index assay (IVDMIA) device to be cleared by the FDA. In July 2007, the FDA issued a draft guidance document to address premarket pathways and postmarket requirements for IVDMIAs. IVDMIA tests combine the values of multiple variables to yield a single, patient-specific result.

Nearly every cell of the body contains a full set of chromosomes and identical genes but only a fraction of these genes are turned on or expressed in any given cell. Gene expression occurs when certain molecular information contained within DNA is transcribed to create molecules known as RNA. These molecules in turn make the proteins that perform most of the critical functions of cells.

Microarray technology can simultaneously measure gene expression levels of large numbers of genes. Small DNA fragments are placed or arrayed on a slide and then RNA, which has been extracted from the tumor tissue and labeled with a fluorescent marker, is spread over this "microarray."

Since RNA binds to its complementary DNA strand, how much binding occurs indicates how active the gene being evaluated is. This can be determined by putting the array under a scanning microscope and measuring the intensity of the fluorescent light at each point on the array.

Pathwork’s proprietary software converts the scanned image data to gene expression measurements. The gene expression patterns are compared with known gene expression patterns in the database that correspond to different tumor types.

The Pathwork Tissue of Origin test has been found to provide patterns that confirm existing tissue of origin of the 15 common tumor types using standard clinical and pathological information. This accuracy of this test is similar to that achieved by expert pathologists using current standards of practice.

PathChip, the gene expression array used in the Pathwork Tissue of Origin test, is custom-designed for Pathwork Diagnostics of Sunnyvale, Calif., by Affymetrix Inc., of Santa Clara, Calif. PathChip is the first custom Affymetrix gene expression array to be cleared for diagnostic use.

Cancer-Survivor Soldier Joins Unit in Iraq

By Pfc. Monika K. Smith, USA
Special to American Forces Press Service

CAMP STRIKER, Iraq, Jan. 10, 2008 - They call him "Tiny," and as with many nicknames, the moniker inaccurately describes Sgt. Jared Squires' stature. At 6 feet, 5 inches tall, the crew chief with Company A, 2nd Battalion, 3rd Aviation Regiment, more than snugly fits into the space allocated for crew chiefs in the Black Hawk helicopters he flies in.

Army Sgt. Jared Squires reviews his pre-flight checklist Jan. 4, 2008. After conquering cancer, Squires joined his unit deployed to Iraq.

Squires, from Los Lunas, N.M., doesn't mind his nickname. He's just happy to be flying again.

In July 2006, Squires learned he had skin cancer. An Army surgeon estimated he had just six years to live.

"When I first found out, I went to the doctor's office and my wife went with me," Squires said. "The doctor came and said, 'I'm sorry to let you know you have malignant melanoma.' I thought, 'I've got two kids. I've got my wife.' ... I wanted to do everything I could right away, because in six years, I might not be there for my boys."

Squires began a series of surgeries and positron emission tomography, or PET, scans, used to detect cancer and the effects of cancer therapy. The cancer spread to the lymph nodes in his left arm. Surgeons removed the lymph nodes, but his body couldn't produce the skin needed to heal his wounds. The fourth surgery was a skin graft to help close the wound, which Squires said was "by far the most painful thing I've ever been through in my life."

Squires said his inability to fly was one of the worst facets of his illness. "I was grounded and couldn't fly after my first surgery," Squires said.

Once Squires completely healed from his surgeries, he began taking interferon to stimulate his body's immune system to fight off cancer. He began 30 days of daily four-hour intravenous treatments.

"The first day of treatment, I could barely walk out on my own strength," Squires said. "I almost had to be carried out."

For 11 months, Squires self-injected interferon three times a week. Though he didn't lose his hair, it did begin to thin out. His days consisted of treatments and sleeping, because his treatments left him exhausted. But he got great support from his unit.

"My company's (family readiness group) stepped up big-time," Squires said. "For two weeks they came to my house and dropped off meals, because my wife was busy taking care of me. It was a lifesaver. It really helped."

Army Sgt. Thomas Lacroix was one of those who stepped up to help the Squires family. A member of Company A, 2-3rd Aviation Regiment, Lacroix has known Squires for seven years. The two met in advanced individual training, served a tour in Korea and then again with the combat aviation brigade.

"(I) felt pretty bad for him," Lacroix said. "I knew his family, his wife, two kids. I tried to do everything I could to help his family out; there wasn't much anyone could really do for him."

As the brigade prepared to deploy to Iraq, Squires was sent to the rear detachment because his illness made him ineligible to deploy. He worked with incoming soldiers who were deploying while continuing with his treatments. He finished his treatments at the end of October and was cleared to fly. But he wasn't content with that. He wanted to deploy.

"I had the opportunity to stay in rear detachment, and I chose not to," Squires said. "I told them 'No, I want to go.' It took a lot of me, from my side, to get them to say, 'Hey, yeah, you're good to go.' They tried to med-board me, and I had to get my oncologist to say, 'He's fine.' They thought I was crazy. My wife knew I wanted to go and that I missed the guys. I missed my friends. We've been together so long, they're my family."

After Squires obtained all the letters he needed from dermatologists and from his oncologist stating he was rid of cancer and capable of deploying, he was on the first plane to Iraq.

"I know it was a big morale boost to have him come out and join the team again," Lacroix said. "It was pretty rough deploying without him. There was a big void in the company."

For the rest of his life, Squires must have routine PET scans and visit a dermatologist every six to nine months, and he must take active measures to prevent cancer from reoccurring.

"I have a 75 percent chance of it coming back," Squires said. "But skin cancer is preventable. It's not like breast cancer. It's not passed down for generations. There's a chance it will come back, but if I take the preventive steps, it shouldn't be a problem."

Lacroix said the company is glad to have Squires back and that his returning was expected.

"That's what he wanted, and he showed he could do it," Lacroix said. "He got better and beat it. He's a true leader. He had the option of staying home and dodging a deployment, but he chose to come out here. The younger guys look up to that."

(Army Pfc. Monika K. Smith serves with 3rd Combat Aviation Brigade.)