- Researchers at The University of Texas MD Anderson Cancer Center have developed a method to quantify tumor-specific total mRNA levels from patient tumor samples. The researchers used this method on tumors from more than 6,500 patients across 15 cancer types and found that higher mRNA levels in cancer cells were correlated with an increased risk of disease progression and poor survival. The study was published in Nature Biotechnology.
- The researchers at Johns Hopkins University investigated age-related mechanisms in melanoma metastasizing. While age-related changes suppress the growth of melanoma cells in primary tumors, this new study established aging as the factor that increased the spread of cancer cells to distant organs. This multicenter study was published in Nature.
- Although cancer cells can have thousands of mutations in their DNA, only some drive cancer progression. Scientists from MIT created a computer model that can quickly scan the genome of cancer cells and identify mutations that occur most frequently and thus potentially are responsible for driving tumor growth. The study was published in Nature Biotechnology.
- A researcher from the University of Texas synthesized a new molecule (ERX-41) that had proved, in in-vitro and animal experiments, to be effective against a broad spectrum of hard-to-treat cancers, including triple-negative breast cancer, pancreatic and ovarian cancers, and glioblastoma. The study was published in Nature Cancer.
- Cancer vaccines are on the rise as a cancer treatment modality. They work by inducing an immune response, but tumors often resist this response via an immune escape mechanism. A group of researchers from Dana-Farber Cancer Institute, Harvard Medical School, and other institutions created a new cancer vaccine targeting this mechanism and increasing immune antibody levels. The vaccine was studied on animals, and human trials are expected to come next. The study was published in Nature.
Author Archives: Marina
“By-product” Search Results in Systematic Review Searches
Systematic Review (SR) searching adopts both systematic and comprehensive approaches with the goal of retrieving, ideally, all the literature relevant to the focused question at the base of your Systematic Review. Typically, an expert searcher, such as an information professional, uses a combination of keywords qualified with field tags (e.g. [tiab] field tag in PubMed related to title and abstract fields of PubMed records) and subject headings (e.g. MeSH in PubMed and EmTree in Embase) for SR searching.
When selecting the terms for an SR, it is best to focus strictly on the terms directly related to the subject or clinical question being addressed. Occasionally it can be appropriate to expand the search to a slightly broader focus to retrieve literature where the exact subject matter may be discussed within the context of other subjects within a broader question.
An example of this expanded search: If the SR is focused on breast cancer surgery, a broader focus would be to look at any/all cancer surgeries wherein breast cancer specific surgery may be discussed.
All search approaches, whether broad or narrow, must be reflected in transparent and reproducible documented search strategies. It is important to remember that there is no “perfect” comprehensive search strategy that will only retrieve relevant citations. It is to be expected that any search, especially a comprehensive SR search, will retrieve many more citations than are actually relevant to the question being asked. Part of the SR process is excluding these irrelevant citations through multiple steps, explained in PRISMA.
However, there is another category besides relevant and irrelevant results, that is typically retrieved – these citations are related to aspects of your topic you did not consider when asking your clinical question and devising your search strategies. These “by-products” might appear important enough that they should be included in your review, but this will be deterring from your original question.
Example: Your SR is on cancer patients’ attitude to health. You devise a comprehensive search strategy and include relevant search terms. As you begin screening the retrieved citations you realize that many of the articles actually focus on health education as it relates to attitudes. You may want to simply add health education as an additional aspect of your SR since it appears to be a valuable aspect of cancer patients’ health attitudes.
The issue with this approach is that unless you backtrack and revise your clinical question and search strategies (and thus essentially starting over from the beginning), your results and conclusions would deviate from the actual question that was proposed initially. If health education was not addressed in your original clinical question and reflected in your search strategies, it would be improper to include it in the final SR as there is likely an entire body of literature that was missed and thus any systematic conclusions could not be made regarding it.
Instead, these “by-product” citations (health education articles that came up in search results for health attitudes) should be treated as irrelevant to the systematic review you are conducting. A potential solution could be mentioning in the discussion section that from this review it was discovered that education is strongly tied to cancer patients’ attitudes toward their disease and their health and that it would be worthwhile to conduct a future review looking at how education can impact these views.
Takeaway: Try not to include “by-product” topics in your final review and analysis.
Salt Levels in Breast Cancer Tumors, Bacteria Linked to Prostatic Cancer and More
- Researchers from the UK used sodium magnetic resonance imaging (MRI) to discover, in a preclinical study, that tumors, unlike healthy tissue, had elevated sodium concentration ([Na+]). The findings demonstrated that sodium levels in tumors of breast cancer patients could be predictors of cancer aggressiveness and the potential efficacy of chemotherapy treatment. The study was published in British Journal of Cancer.
- A study led by the University of Granada in Spain discovered that men with prostate cancer had lower levels of melatonin, the sleep-inducing hormone, than men without the disease. The study was published in Journal of Urology.
- Scientists in the UK have discovered bacteria linked to aggressive prostate cancer. By performing genetic analyses on the urine and prostate tissue, they found five species of bacteria connected to cancer progression. If the role of bacteria is confirmed in the ongoing experiments, that will pave the way for new ways of prevention and treatment of prostate cancer. The study was published in European Urology Oncology.
- Researchers from the University of Wisconsin have created a drug-releasing hydrogel to reduce the possibility of local cancer recurrence (colon cancer, melanoma, and triple-negative breast cancer) after surgery. Human clinical trials are needed as this was a preclinical study done on mice. Those findings could potentially be used in other types of cancer. The study was published in Nature Communications.
- The new research by Genetch, Inc., the Howard Hughes Medical Institute and the Peter MacCallum Cancer Center explained how tumor cells or cells infected by pathogens resist killing by T cells, known as cytotoxic T lymphocytes (CTLs).The in vitro study demonstrated that ESCRT protein recruitment helped cancer cells resist CTL attacks. The study was published in Science and commented upon in the same issue.