Cancer became a deadly disease because of its ability to spread to other parts of the body. Once the cancer cells have spread, it becomes extremely difficult to treat, leading to the patient's untimely death. In order to learn more about cancer metastasis, a researcher at Purdue University developed a lifelike cancer environment to predict how drugs may stop metastasis.

Lifelike Cancer Environment Out of Polymer

Luis Solorio at Purdue University developed the environment using polymer materials. Solorio and the research team proposed the method called 3D writing, instead of 3D printing that is normally used to recreate the biological environment, but which is not realistic enough for drug screening purposes.

The device they used is called 3D jet writer that functions similarly to a 3D printer by producing polymer microtissues. The researchers turned these polymer microtissues into smaller shapes and with a more realistic scale, with pores large enough for real cells to enter the polymer, like what occurs normally in the human body. They tested the polymer microtissues in mice and drew in cancer cells to areas where cancer does not develop normally. The test proved that the materials can recreate cancer environments where certain conditions are favorable for malignant cells.

"We need a much finer resolution than what a 3D printer can create. Ideally, we could use our system as an unbiased drug screening platform where we could screen thousands of compounds, hopefully, get data within a week, and get it back to a clinician so that it's all within a relevant time frame," said Luis Solorio, an assistant professor of biomedical engineering at Purdue.

The goal of creating a feasible cancer environment is to allow researchers study how current and new drugs interact with cancer cells, and how capable the anti-cancer drugs in targeting receptors carried by these malignant cells.

Metastatic Cancer

Metastasis is the reason why cancer is a very serious disease. Normally, cancer cells start and grow locally, within a specific type of tissue or in an organ. However, tissues and organs are interconnected to numerous blood vessels that supply nutrients and oxygen, and lymph vessels that pick up fluids that leak into the tissues from the bloodstream and then return it to the circulatory system.

Sometimes, tumors break off and go into the bloodstream or the lymph vessels. Using these channels, tumors can spread to other parts of the body. For instance, the cancer of the liver starts in the organ associated with cirrhosis, a complication due to liver cell loss and irreversible scarring, then it can travel to the brain and the lungs using the mentioned channels. The cancers in the brain and lungs are called metastatic cancer or in some cases, stage IV cancer.

According to the National Cancer Institute, most cancer cells that spread die at some point. But if the conditions are favorable, some malignant cells can form new tumors in other sites. Also, metastatic cancer cells can lay dormant for years and may grow later on, depending on the conditions.

Like localized cancer, metastatic cancer may not cause symptoms at all. If any symptoms occur, the characteristics would be related to the organ where it has spread, such as:

- Body pain and bone fractures that indicate the spread of cancer to the bone.

- Dizziness, headaches or seizures can be symptoms of metastatic brain cancer.

- Shortness of breath may be a sign of cancer spreading to the lungs.

- Increased abdominal girth or yellow skin can be indicators of metastatic cancer of the liver.

Another condition that may occur in a cancer patient is called paraneoplastic syndrome. It occurs when the immune system responds to a tumor, instead of the disease itself. The condition causes several symptoms in different areas of the body, such as muscle cramps, muscle weakness, elevated calcium in the blood, and clubbed fingers. Paraneoplastic syndrome is a common condition associated with cancer of the lungs, the kidneys, liver, pancreas, and breast.

Treatment of Metastatic Cancer

Some types of metastatic cancer can be cured with current treatments, but in general, cancer that has spread is very difficult to control. The doctor would normally recommend treatment that can help slow down or stop the cancer growth or relieve symptoms of the disease.

Typically, cancer survival rate uses the overall five-year measurement, but metastatic cancer significantly shortens this measure. The survival rate is also determined by percentage, such as 78 percent overall five-year survival rate for people with cancer of the urinary bladder.

Once the metastatic cancer is uncontrollable, the doctors would notify about end-of-life care that should be discussed with the patient and their loved ones. Continuing cancer treatment remains available to lengthen the patient's life with the option to receive palliative medicine to relieve the side effects of treatment.

[메디컬리포트=Ralph Chen 기자]