Vaccines: The next frontier of lung cancer treatment and prevention
Editor's note: November is Lung Cancer Awareness Month.
By Jessica Saenz
Physicians have used vaccines for centuries to prime the immune system to recognize and combat specific pathogens, such as viruses and bacteria, before they cause illness. As medical science's understanding of the immune system has evolved, new possibilities for vaccine use have emerged.
Today, cancer researchers are exploring vaccines' potential to treat and prevent certain types of cancer, including lung cancer, which continues to be the leading cause of cancer death worldwide despite reduced rates of tobacco use.
Keith Knutson, Ph.D., a Mayo Clinic immunologist and cancer vaccine researcher, discusses lung cancer vaccine research at Mayo Clinic and how physicians and researchers may use vaccine technology in other types of cancer.
What is a cancer vaccine?
Cancer vaccines are a type of immunotherapy, which is a treatment that can use the immune system to destroy cancer cells. They can be preventive or therapeutic. The HPV vaccine, for example, helps prevent cancer by protecting against HPV infection, which can cause certain types of cancer. Therapeutic cancer vaccines can treat cancer or reduce cancer recurrence, and physicians are using them for some patients in clinical trials.
"A cancer vaccine is similar to an infectious disease vaccine," says Dr. Knutson. "It's a medicine we give to stimulate the immune system with antigens derived from cancer." Antigens are any substance that activates an immune response in the body. Dr. Knutson says that sometimes, physicians can use these antigens to train the immune system to fight cancer.
The immune system can often recognize cancer cells and destroy them before they can grow and spread. However, cancer cells have mechanisms that help them evade the immune system. Cancer vaccines can help the immune system overcome these mechanisms and attack cancer cells.
A personalized lung cancer vaccine
Each type of cancer varies based on the type of tissue in which it originated, the changes or mutations to the DNA within its cells, and from person to person. Cancer experts sometimes use these individual cancer traits to provide more targeted treatment.
"Because cancer grows so rapidly, there are lots of defects in cancer cells. They don't repair their DNA or RNA well enough, and they accumulate mutations," says Dr. Knutson. DNA contains the genetic instructions for cell function, and RNA conveys those instructions to produce proteins with distinct roles in the cell. Errors in the genetic instructions, called mutations, represent unique targets for therapy.
This targeted approach is the foundation for one of the vaccines in development at Mayo Clinic.
"We have developed personalized vaccines for lung cancer," says Dr. Knutson. "We can take part of the cancer through a biopsy, sequence the cancer, and use the information in the DNA and RNA to make a vaccine for that particular cancer."
Dr. Knutson says Mayo Clinic researchers are exploring two ways to use this vaccine: to prevent recurrence and to reduce cancer spread.
"Even when the tumor is gone, patients have a high risk of their cancer coming back. After the tumor has been removed with conventional therapies, we can train the immune system by stimulating it to prevent that type of cancer from returning. The hope is that the cells we stimulate with vaccines can recognize and seek out cancer and destroy it before it becomes a problem," he says.
In addition to recurrence prevention, Mayo Clinic researchers hope to understand how well the vaccine can reduce cancer spread in advanced lung cancer. "Often, patients have bulky tumors throughout their body. The immune system can travel and seek out targets. The question is: Can we stimulate the immune system to generate enough T cells to find and attack these tumors in various parts of the body?"
A preventive vaccine for lung cancers with specific genetic characteristics
Dr. Knutson says Mayo Clinic will soon begin investigating the use of a primary prevention vaccine for breast cancer that can also be used to stop some types of lung cancer from developing. Unlike a personalized vaccine, which relies on genetic information from existing cancer, this vaccine uses antigens for some of the common oncogenes overexpressed in breast cancer, which can also be found in some lung cancers. Oncogenes are mutated genes with the potential to cause cancer. When they are overexpressed, they make too many copies of themselves, which can promote cancer growth.
One antigen included in this vaccine targets human epidermal growth factor receptor 2 (HER2) overexpression. HER2 is responsible for cell growth and division and is overexpressed in about 13% to 20% of non-small cell lung cancers (NSCLC), the most common type of lung cancer. The vaccine also includes several other antigens, including one for MUC1 overexpression found in 80% of NSCLCs.
Dr. Knutson says researchers could use this technology to prevent other types of cancer. "HER2 for example, is overexpressed in ovarian cancer. So, if we had a vaccine that prevented breast and lung cancer by targeting HER2, it has the potential to treat or prevent other types of cancer with that overexpression."
Strides made in cancer vaccine development over the last few decades have given cancer researchers a glimpse at the possibilities they hold for lung cancer treatment, explains Dr. Knutson.
"Fifty years ago, we didn't have the capabilities we have now. Our capabilities are rapidly changing and accumulating," he says. "Over the next 20 years, we're going to see some great improvements in how we use vaccines to activate the immune system to suppress cancer development, treat cancer and prevent it from coming back."
Learn more
Learn more about lung cancer and find a clinical trial at Mayo Clinic.
Join the Lung Cancer Support Group on Mayo Clinic Connect, an online community moderated by Mayo Clinic for patients and caregivers.
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