Cancer is a collection of over 200 diseases where the only common denominator is rogue cells1,2. The ways in which a cell can go rogue is so varied that cancer has its own separate biology where order and normalcy are not readily apparent. Cancer does not even have to be solid. Indeed, blood cancers like leukemia and lymphomas account for about 10% of new cancer diagnoses in the US3. Our understanding of cancer is continually being refined, and in preparation for our visit to the 2017 American Association for Cancer Research (AACR) conference, this blog post will give a brief overview of human history with cancer, highlight some accomplishments in cancer research, and discuss two future directions for cancer therapy research.
Fossilized bones and mummies of ancient Egypt provide some of the earliest evidence of cancer, and the first recorded description of cancer dates back to circa 3000 BC characterizing breast tumors as a disease for which “there is no treatment5.” It would not be until 1775 when Percivall Pott established the first clear link between an environmental factor and cancer development by relating chimney soot exposure with scrotum cancer6. Roughly another 70 years passed before Rudolf Virchow became the first to recognize leukemia by connecting inflammation to cancer. In the early 1900s, the founding of nonprofit organizations like the AACR and The American Cancer Society (ACS) spearheaded a movement toward a proverbial cure for cancer by organizing and promoting cancer research efforts. In 1971, Richard Nixon started the veritable war on cancer by enacting the National Cancer Act. A slew of anti-cancer drugs such as tamoxifen, anastrozole, and rituximab were developed shortly thereafter along with the identification of such seminal tumor suppressor genes and oncogenes as TP53, HER2, and BRCA between 1978 and 1997.
Today, our efforts largely focus on cancer prevention, earlier diagnosis, defining molecular mechanisms, and developing treatments that offer better quality of life. Cancer researchers face many hurdles in these endeavors. For example, cancerous cells share molecular and biochemical machinery with normal cells making precise drug treatments difficult to develop. Treatments for cancer must also be currently tailored to individual cases since cancer is not a single disease with a common cause. As such, there is growing popularity for developing both targeted therapies and immunotherapies7. Targeted cancer therapies utilize the molecular and biochemical differences between cancer cells and normal cells revealed in cancer biology research. By targeting specific and deliberately chosen molecular mechanisms, targeted drugs are less likely to have off-target effects and thus, side effects are mitigated. Examples of targets for such therapies are proteins that are abundant in cancer cells but low or non-existent in normal cells such as HER2, chromosomal abnormalities such as BCR-ABL, or mutant proteins. Unfortunately, targeted therapeutics are not without limitations. Drugs can be extremely difficult to develop due to the functional nature or structure of many targets, and cancer cells can gain resistance to targeted therapies.
Cancer immunotherapies are considered a subset of targeted therapies because molecular targets are utilized. Immunotherapies have the effect of a more systemic approach by exploiting the natural properties of the body’s immune system to detect and destroy cancer cells as they develop. One particular type of immunotherapy that has proven to be effective is the therapeutic antibody. Therapeutic antibodies include antibody-drug conjugates, which are cancer cell-targeting antibodies chemically linked to a death-inducing payload, and apoptosis-inducing antibodies that utilize the complement system. These therapies are thought to yield fewer or less severe side effects than more standard systemic approaches like chemotherapy by using the normal properties of the immune system. Another promising type of immunotherapy is chimeric antigen receptor (CAR) T-cell therapy, which is currently in the early clinical trial phase for patients with blood cancers8,9. As mentioned earlier, cancer cells can develop resistance and cancerous tissues can sometimes be difficult to access. Furthermore, tumors are not always homogeneous in their target antigen expression. Due to these limitations, immunotherapy is often used in combination with other therapies.
Since the 1970s, the percentage of people diagnosed with cancer who survive 10 or more years has double and the mortality rates have generally declined. Research has pinpointed numerous carcinogens to avoid in our lifestyle to prevent or delay cancer, and advanced screening technologies have made diagnosing cancer much more sensitive and reliable. The scientific community has made outstanding progress toward fighting cancer, however much work remains as we continue to unravel the mechanisms driving cancer progression and disseminate this information to our communities.
ScienCell will be participating in the 2017 AACR conference from April 2 through 5. Please visit booth 2157 to learn about our products and research. ScienCell supplies over 260 human and animal primary cell types and over 70 types of specialty media for cell culture research. In addition, ScienCell also offers a variety of cell-based assay kits to analyze cell metabolism, oxidative stress, enzyme activity, and cell growth. ScienCell also facilitates gene expression analysis research with pre-designed GeneQuery qPCR Array Kits and individual GeneQuery qPCR primers. Review our full products catalog online at www.sciencellonline.com.
- Hanahan, D. & Weinberg. R.A. (2000). The hallmarks of cancer. Cell. 100: 57-70.
- Hanahan, D. & Weinberg, R.A. (2011). Hallmarks of cancer: The next generation. Cell. 144: 646-674.
- Wang, Z., et al. (2017). New development in CAR-T cell therapy. J Hematol Oncol. 10: 53.
- Sha, H.H., et al. (2017). Chimaeric antigen receptor T-cell therapy for tumor immunotherapy. Biosci Rep. 37: BSR20160332.
Image: ACS campaign poster (http://www.check-six.com/Affiliates/spock.jpg)
Research and Development Scientist, Sciencell