We are moving forward in the fight against breast cancer. In 2017 alone, a PubMed search generated nearly 13,500 articles related to breast cancer research published in peer-reviews to date. This made selecting our top five breakthroughs quite a challenge. This is a good problem to have.
Breast cancer is the second most common cancer in women. Nearly 253,000 women will be diagnosed with breast cancer in 2017. This number has remained constant for the last 10 years. The good news is that mortality rates have decreased an average of 1.8% each year from 2005 to 2014. Increased survival rates coupled with ongoing innovative research provide hope for the future.
Below are our top five breakthroughs in new breast cancer treatments or developments in potential markers and causes for 2017.
BRCA1 and BRCA2 Research
The link between BRCA1 and BRCA2 and breast cancer risk is well established. While everyone has these genes, some people have an inherited mutation in one or both of these genes that increases the risk of breast cancer. These mutations affect between 1 in 400 and 1 in 800 people in the U.S. Many women with this mutation decide to have preventive mastectomies due to their higher risk of breast cancer.
The drug Lynparza (olaparib) is already FDA-approved for women with BRCA-related ovarian cancer. Therefore researchers theorized it might be helpful in treating breast cancer related to the same gene mutation. A study was conducted on 302 women with the inherited BRCA mutation who had metastatic breast cancer (cancer that spread to other areas of their body). Olaparib delayed cancer progression by about 3 months and caused tumors to shrink. After 14 months of treatment, women an olaparib regimen had on average, a 42% lower risk of cancer progression compared to those who received another round of chemotherapy. Although more studies are needed, these findings may be practice-changing. If approved, olaparib could postpone IV chemotherapy and its associated side effects like hair loss and low white blood cell counts.
HER2-Positive Breast Cancer Research
About one in 10 breast cancers are HER2-positive (HER2+). This is a genetic form of the disease that's particularly aggressive and can spread to other parts of the body. Current treatments for this type of breast cancer only deactivate cancer cells, but these can reactivate at any time. In some invasive forms of breast cancer, excessive levels of HER2 leads to uncontrolled growth of cells, making it far more difficult to treat.
In July 2017, the U.S. Food and Drug Administration (FDA) approved Nerlynx (neratinib). This is the first drug designed to prevent return of HER2+ breast cancer. It works by blocking enzymes that fuel cancer-cell growth. In clinical trials, Nerlynx was evaluated on more than 2,800 women with early-stage HER2+ breast cancer who had completed treatment with the chemotherapy drug trastuzumab. After 2 years, 94.2% of users did not experience recurrence compared to 91.9% treated with an inactive placebo.
Estrogen-Positive Breast Cancer Research
An estimated 75-80% of breast cancers are estrogen positive (ER+). Anti-estrogen therapy with tamoxifen and/or an aromatase inhibitor is the standard treatment approach for ER+ breast cancer. These drugs work by attaching to a molecule called the estrogen receptor in cancer cells, thereby preventing estrogen from binding to the receptor. Unfortunately, as many as one-third of these cancers eventually become treatment resistant.
A novel molecule called ERX-11 was developed and tested on mice and human cancer cells by researchers at UT Southwestern Simmons Cancer Center. The drug works by blocking the estrogen receptor from interacting with the co-regulator proteins that cause a tumor's growth. Researchers believe ERX-1 holds future promise as a first-line breast cancer therapy.
Aging and Breast Cancer Research
Increasing age is one of the factors associated with a higher risk of breast cancer along with being overweight after menopause, alcohol intake, and family history. The contributing biologic mechanisms that increase the risk are poorly understood. A new study by researchers at Dartmouth Norris Cotton Cancer Center provides insights on age-related changes that may predispose breast tissue cells to becoming cancerous. This research is unique in that it attempted to characterize molecular differences in healthy normal tissue associated with cancer risk factors.
The study demonstrated age is the breast cancer risk factor most strongly associated with normal breast DNA methylation differences. Moreover, regions in the genome where age-related DNA methylation changes occurred were especially sensitive to cancer disruption. Researchers hope these findings provide a foundation for future studies evaluating modifiable risk factors or disease prevention interventions to help reduce age-related risk.
Identification of Lysyl Oxidase (Lox)
Previous research identified the role of lysyl oxidase or Lox in cancer metastasis to the bone and uncovered a link to lung, bowel, prostate, and pancreatic cancer. Now researchers have revealed Lox enables breast cancer cells to latch on to growth receptors – sparking more rapid growth. In a mouse model study, a novel type of drug had promising results for thwarting this action. When tested on mice, the drug halted the protein’s capacity to spark cancer cell growth, slowing both the growth of tumors and the rate at which cells multiplied. This is the first time Lox has been shown to have a controlling influence on tumor growth.
Although more studies are needed, researchers are hopeful similar inhibitors that disrupted Lox’s ability to promote cancer cell growth in mice might be able to slow or block cancer progression in humans.
What do you think about the top breast cancer breakthroughs of 2017? Please share below.