A promising new study shows it’s possible to turn cancer cells back into healthy tissue.
Researchers have found that by reactivating a single gene, they were able to do just that in mice with colorectal cancer.
The gene, adenomatous polyposis coli (Apc), is a tumor suppressor. Up to 90 percent of colorectal tumors have an inactive mutation of this gene.
Researchers began by suppressing the Apc gene in mice. That activated what is known as the Wnt signal pathway, which helps cancer cells grow and survive.
Then they reactivated the Apc gene. Wnt signals returned to normal and cancerous tumors stopped growing. Normal intestinal function was restored in four days. The tumors were gone within two weeks. There were no signs of cancer relapse during the six-month follow-up.
The same approach turned out to be effective in mice with colorectal cancer tumors with Kras and p53 mutations. In humans, about half of colorectal tumors have these mutations.
Revolutionizing Colorectal Cancer Treatment
The study is published in the journal Cell. Scott Lowe, Ph.D., of the Memorial Sloan Kettering Cancer Center, is the study’s senior author.
"Treatment regimens for advanced colorectal cancer involve combination chemotherapies that are toxic and largely ineffective, yet have remained the backbone of therapy over the last decade,” said Lowe.
Apc reactivation may be the key to improved treatment for colorectal cancer. It is doubtful it will be helpful in other types of cancer. However, this approach may prove useful in future cancer studies.
"The concept of identifying tumor-specific driving mutations is a major focus of many laboratories around the world," said Lukas Dow, Ph.D., of Weill Cornell Medical College, the study’s first author.
"If we can define which types of mutations and changes are the critical events driving tumor growth, we will be better equipped to identify the most appropriate treatments for individual cancers," said Dow.
Colorectal Cancer Is Widespread
Colorectal cancer begins in the colon or rectum. It's the second top cause of cancer death in developed countries.
According to the Surveillance, Epidemiology, and End Results Program, in 2012, there were 1,168,929 people living with colon and rectal cancer in the United States.
It is estimated that there will be 132,700 new cases of colorectal cancer in the United States in 2015. About 49,700 people will lose their lives to this disease. Worldwide, colorectal cancer is responsible for 700,000 deaths each year.
Internist and gastroenterologist Dr. Frank Malkin is hopeful about genetic research into colorectal cancer. He told Healthline: “They’ve identified a suppressor gene that can turn a tumor on and off. It can suppress the cancer and destroy it rapidly. That’s very promising.”
Changing How Cancer Is Treated
Surgery, chemotherapy, and radiation. That’s how cancer cells are usually removed or killed off.
These harsh treatments can take a lasting toll. Easier and more effective treatments could change the lives of cancer patients.
Michelle Gordon, D.O., FACOS, FACS, finds it encouraging. “If this treatment is to be believed, all current modalities will be obsolete.”
Both Malkin and Gordon caution that it’s too soon for this research to affect colorectal cancer treatment in humans.
“There are so many unknowns when taking a mouse model to humans,” Gordon told Healthline. “This may be the foundational step that will lead to curing most colorectal cancers. This study can provide hope to future generations of colorectal cancer [patients], but I believe a cure is decades away.”
Researchers know Apc mutations initiate colorectal cancer. They don’t yet know if it is also involved in tumor growth after cancer has developed.
Next, the research team will focus on Apc reactivation in distant metastases. Another goal is to find out precisely how Apc works. That will help scientists develop safe treatments that change cancer cells into normal cells. Such a drug could make colorectal cancer treatment easier, faster, and safer.
How this research will impact other types of cancer remains to be seen.
Stopping Colon Cancer Before It Starts
“Cure rates for colorectal cancers are better than they used to be, especially when treated in the early stages,” said Malkin. But it’s still better to stop it before it starts.
According to Malkin, the number of colon cancer cases has dropped dramatically since routine colonoscopy screening began. A colonoscopy allows doctors to find and remove polyps before they turn cancerous.
Malkin looks forward to genetic research that will identify those at greater risk for colorectal cancers.
“Right now, we’re using colonoscopy to screen people over 50, most who don’t have the genetic predisposition and will never get colorectal cancer,” he said. “We don’t yet have the genetic studies that would help us identify high-risk patients so we don’t have to screen everyone.”