By Caroline Cochrane
Cancer is a disease that affects almost everyone, directly or indirectly. In 2020 alone, the US is expected to have 1.8 million new cancer diagnoses and 606,520 cancer deaths (Cancer Facts & Figures 2020 | American Cancer Society, 2020). These numbers are alarming, yet believable. It seems that everyone knows someone with cancer. Because it is so common in the modern-day, research on a potential cure and better treatments has become a vast field in the world of medical research. Chemotherapy has been changed immensely through the years, as well as different methods of detection. In the past decade, even some high schoolers have taken part in developing better ways to diagnose and treat cancer. Some promising news is that the 5-year relative survival rate of all cancers in the US from 2010-2016 was 67.4%, a 3.6% increase since 2000 with an upward trend (Cancer of Any Site – Cancer Stat Facts, 2020). This trend can be greatly attributed to the medical advancements made in oncology in the past few decades.
Many promising treatments currently being developed involve genetic manipulation. The Human Genome Project was an effort from US scientists to map out the entire human genome to understand precisely how the human body works and how we can use genetics to predict risk factors or even treat diseases. This research, finished in 2003, has allowed for many advancements in medical research. Genetics in oncology specifically have played a substantial role in diagnosis and treatment research because not only are doctors able to identify who may be at more risk for specific cancers, they now understand exactly how cancer works and the specific genetic mutations that form tumors. Additionally, Scientists are now able to look at the DNA of various cells and viruses to understand how they work and how to control the expression of different traits. These scientists have identified parts of viral DNA that threaten humans and have been able to successfully edit these genes out of expression and manipulate the target cells of a virus. Using this technology, Oncolytic Virology was established.
Oncolytic Virology is an emerging field in which viruses are genetically modified to preferentially infect and lyse tumor cells, thereby inducing an immune response in which the patient’s body attacks the tumor. Research is currently being conducted on treatments for colorectal cancer, breast cancer, pancreatic cancer, and many other cancers, especially concerning late-stage cancer where surgery may not be successful. As this is a relatively new field, most research is still in still in its early stages with little results. One specific treatment, however, has already been approved by the FDA and is soon advancing towards becoming a regular treatment for melanoma: Talimogene Laherparepvec.
Talimogene Laherparepvec, known commonly as T-Vec, is the first of its kind approved by the FDA. It is an oncolytic virus, so it works by preferentially targeting tumors and initiating an immune response from the body. Scientists genetically engineered a type 1 herpes simplex virus to simultaneously be void of its natural neurotropic, infectious properties and increasingly selective towards cancer cells. This modified virus is injected into the center of a cancerous tumor, specifically melanoma, and begins to work relatively quickly and with limited side effects.
One remarkable aspect of T-Vec and Oncolytic Virology is that there is no evidence that success rates of these treatments are different for any person of a different race or gender. This is extremely important in the field of Oncology because there are large morbidity gaps between different demographics. According to the National Cancer Institute, “Among both men and women, blacks have the highest cancer death rates, and Asian/Pacific Islanders have the lowest cancer death rates. The death rate for men was 185.5 per 100,000 men per year. The death rate for women was 133.5 per 100,000 women per year” (Cancer Disparities – Cancer Stat Facts, 2020). Treatments such as T-Vec with little disparity in success rates leave hope that in the future, fewer people will die of poor and biased research. In addition, T-Vec has already begun to change the way new treatments are developed and how research is conducted. It has set a precedent for a major upturn in the elimination of cancerous tumors in humans.
In the near future, this research will have a profound effect on cancer treatment. Because T-Vec has been such a success, there is research in clinical trials to use different retroviruses such to treat different types of cancer. Several are already showing great promise in efficacy. Oncolytic Virology is anticipated to be used both as a singular treatment and in conjunction with other treatments. Cancer patients who would currently be told that there is no hope for treatment in the future may have little worry about their survival, especially patients who have unresectable tumors or are suffering from metastases. Oncolytic Virology is revolutionary and may change the face of cancer treatment forever.
Cancer Disparities – Cancer Stat Facts. SEER. 2020 [accessed 2020 Sep 17]. https://seer.cancer.gov/statfacts/html/disparities.html
The Human Genome Project. Genome.gov. 2020 [accessed 2020 Sep 17]. https://www.genome.gov/human-genome-project
Cancer of Any Site – Cancer Stat Facts. SEER. 2020 [accessed 2020 Sep 17]. https://seer.cancer.gov/statfacts/html/all.html
Cancer Facts & Figures 2020 | American Cancer Society. Cancer.org. 2020 [accessed 2020 Sep 17 https://www.cancer.org/research/cancer-facts-statistics/all-cancer-facts-figures/cancer-facts-figures-2020.html
Eissa I, Bustos-Villalobos I, Ichinose T, Matsumura S, Naoe Y, Miyajima N, Morimoto D, Mukoyama N, Zhiwen W, Tanaka M et al. The Current Status and Future Prospects of Oncolytic Viruses in Clinical Trials against Melanoma, Glioma, Pancreatic, and Breast Cancers. Cancers. 2018;10(10):356.
Grigg C, Blake Z, Gartrell R, Sacher A, Taback B, Saenger Y. Talimogene laherparepvec (T-Vec) for the treatment of melanoma and other cancers. Seminars in Oncology. 2016;43(6):638-646.
Conry R, Westbrook B, McKee S, Norwood T. Talimogene laherparepvec: First in class oncolytic virotherapy. Human Vaccines & Immunotherapeutics. 2018;14(4):839-846.
Featured Image: Shutterstock. Oncolytic Virology.; 2020 [accessed 2020 Sep 17]. https://encryptedtbn0.gstatic.com/images?q=tbn%3AANd9GcRU1_Ejx4n-xcU49N2f38JGXzZ__HMGN_8lWw&usqp=CAU