Among the leading causes of death worldwide, cancer is ranked second after cardiovascular disease. As this disease poses a major public health burden, scientists have worked tirelessly to develop treatment, prevention, and early detection measures. That said, many researchers have been hard at work for years on vaccines to prevent cancer, most notably for pancreatic, colon, and breast cancer.
A woman in the United States has an average risk of developing breast cancer at some point in her life, about 13% according to the American Cancer Society. There are, however, specific gene mutations that increase a woman’s chances of developing breast cancer. Having a BRCA mutation increases your chances of developing breast cancer by 45% to 85% according to Johns Hopkins Medicine.
A revolutionary study at Penn Medicine is trying to paint a more hopeful future for women who are at high risk for developing breast cancer, which is responsible for around 43,000 deaths annually in the United States alone.
The trial will focus on intervening early in BRCA1 and BRCA2 breast cancers to alter their normal progression. Their goal is to determine whether vaccinating individuals with the genetic mutations BRCA1 or BRCA2, putting them at increased risk of breast cancer, will lower their risk of recurrence or developing cancer in the first place.
Are these trials likely to succeed? Penn Medicine is not the first to explore the effectiveness of a cancer vaccine, despite it seeming like a novel approach.
A Cancer Vaccine Isn’t Science Fiction
Although cancer vaccines exist, they work differently from what Penn Medicine is currently developing. Human papillomavirus (HPV) vaccines, for example, prevent cervical cancer through the targeting of the HPV strains responsible for tumor development. In spite of the HPV vaccines’ effectiveness, cancer is rarely caused by viruses, so enabling the body to identify tumor cells would be invaluable for other types of cancer.
Researchers have therefore begun focusing on reducing the chances of recurrence among those who have already developed cancer. As a result, many newly developed treatments can train the immune system to recognize and destroy cancer cells.
Immunotherapy treatments are used to treat advanced disease, which has metastasized, as a method of last resort in some patients. There are some medical experts, however, who are using vaccines earlier, with some success, in training the immune system to fight lung, skin, and kidney cancers in an effort to prevent reoccurrence.
In the case of breast cancer, it’s a different story.
The Advancements And Challenges With A Breast Cancer Vaccine
When it comes to the treatment of breast cancer, immunotherapy treatments fall short. “A lot of breast tumors do not attract the immune system, so there is very little in the way of an immune response,” Dr. Robert Vonderheide, director of the Abramson Cancer Center at Penn Medicine, explained to TIME. “That’s where vaccines come in because they are designed to start an immune response that can then be elaborated.”
A vaccine’s principal function, according to Vonderheide, is to optimize the immune response by teaching cells to recognize cancer cells as foreign. If this is possible in a breast cancer vaccine, Vonderheide believes it may be possible not just to prevent recurrences of cancer, but also to prevent it from developing in the first place. Researchers at Penn Medicine may be on the verge of achieving that goal.
Dr. Susan Domchek is investigating the safety of a vaccine targeting telomerase, an enzyme that modulates the rate at which breast cancer cells divide. Cells that divide rapidly, such as cancer cells, produce more telomerase, while cells that function normally have less.
A prospective vaccine could include DNA snippets coding for key parts of telomerase that would train immune cells called T cells to recognize and target excessively telomerase-using cells.
They “stalk the blood to attack and kill those [cancer] cells before anyone even knew they were there,” explained Dr. Domchek to TIME.
While promising, Dr. Vonderheide, a collaborator with Domchek on the trial, explained that getting the T cells to work against the cancer is vital to moving this breast cancer vaccine forward. “We think the best vaccines for cancer will be those that generated T cells,” he stated.
As part of the study, Penn Medicine will enroll 16 people who have been diagnosed with cancer and have the genetic mutations BRCA1 or BRCA2, which puts them at higher risk for breast cancer. A further 28 people with genetic risk, who do not have cancer, will also be studied to see if they are at lower risk of getting cancer if they are vaccinated. The study will take place for two years.
Breast cancer vaccine trial results showing a reduced risk of recurrence or a significant reduction in developing cancer will be considered a great triumph for cancer research, as well as a huge step forward for cancer prevention.
Even as we wait for exciting developments, medical experts still advise women to have regular mammograms and clinical breast exams, especially if they are considered high-risk.