MDD's Oncology Extra
Additional Developments in One of Med-Tech's Key Sectors
Keeping you up to date on recent developments in oncology
Georgetown researchers eye aromatase as key to breast cancer . . . There is no novelty to the assertion that a high count of estrogen receptors in the breast are associated with a higher incidence of breast cancer in post-menopausal women, but researchers at Georgetown University (Washington) believe they have evidence that the role of aromatase, the enzyme known for its role in the synthesis of estrogen, may play a more central role than even estrogen receptors. According to an Aug. 12 statement from Georgetown's Lombardi Cancer Center, several Georgetown researchers published their findings in the Aug. 15 edition of Cancer Research regarding a rodent study that demonstrated that overproduction of aromatase, which converts testosterone into estrogen, “is even more important in pushing breast cancer development than excess production of the estrogen receptor that the hormone uses to activate mammary cells.“ Perhaps even more central to the dynamic is that data from this animal study also indicated that mice that over-expressed aromatase “also expressed more estrogen receptors on the breast cells.“ The statement indicates that this finding, should it hold up to confirmatory efforts, could tip the balance of therapeutic efforts toward aromatase inhibition, noting that Tamoxifen and other estrogen blockers “have long been used to prevent breast cancer and deter recurrence, while aromatase inhibitors are only now being studied as a protectant.“ Priscilla Furth, MD, professor of oncology and medicine at Lombardi, said in the statement that medical science is aware that “estrogen is the fuel that most breast tumors use to grow, and this study shows us that making more estrogen in the breast, right next to cells that can use the hormone as fuel, appears to be a key trigger of early breast cancer.“ However, the study also forced researchers at Lombardi to examine another idea, specifically how central the role of systemic estrogen is to breast cancer. Edgar Díaz-Cruz, PhD, a postdoctoral researcher working with Furth and the lead author of the study, said the effort “appears to help inform a longstanding controversy about whether it is systemic estrogen or estrogen produced in the breast that is the primary risk factor for breast cancer.“ Diaz-Cruz said further, “we've demonstrated that local production of estrogen in mammary tissue is potent enough to spur development of breast cancer, and does not require estrogen from the ovaries or produced from fat tissue, as had been hypothesized.“ The study made use of mice that were genetically engineered with switchable genes for aromatase production in mammary tissue and mice that had an on-off switch for estrogen receptor (ER) production as well, and while animals from both groups exhibited pre-neoplastic tendencies, the aromatase-engineered mice ““exhibited both increased pre-neoplasia and outright development of cancer,“ the statement notes. One unexpected outcome from this study, however, was that aromatase seemed to work to help sustain itself. The statement notes that the researchers participating in this study “also found, to their surprise, that aromatase over-expressing mice expressed more estrogen receptors than did the ER-conditional mice, a predicament that Díaz-Cruz said “is obviously a greater risk for development of breast cancer than just over-expression of estrogen receptors.“ However, Furth asserted that the study did not pump the mice full of aromatase to levels that are unseen in nature. “These were not super large amounts. Comparable levels can be measured in women,“ she said.
NIH announces global cancer seminar . . . Cancer is tough enough to beat in resource-rich nations such as the U.S. and the nations that make up Western Europe, but developing nations are in an even tighter pinch where the various cancers are concerned. Thus, the U.S. National Institutes of Health has announced a seminar scheduled for Aug. 22-23 to foster the advancement of diagnostics and therapeutics for cancer in the developing world. According to the undated statement at the NIH website, a variety of platforms and technologies, such as the lab-on-a-chip diagnostic, can be “can be adapted to bring cancer detection and diagnostics to global health settings.“ NIH states that the unique feature of the conference “is the focus on bioengineering and low cost cancer diagnostic technologies for treatable cancer in international health settings,“ which NIH hopes to achieve by assembling some of the best minds in oncology, public health, and engineering to be found in academia, government, nongovernmental organizations, and industry “to discuss public health needs and cancer detection and diagnostics from several perspectives.“ Among the themes this session will take up are cancer biomarkers, technologies with potential for cancer detection, and diagnosis/prognosis. One of the areas of emphasis will be to foster research into lower-cost diagnostics technologies, but some of the discussions will cover topics such as commercialization and “promising scientific and technological developments.“ NIH indicates that registration for this event is closed, but to be put on a wait list for cancellations, contact NIH's Julia Lam (301-228-4141, lamj@mail.nih.gov).
Hospitals offering reduced-rate CT scans to smokers . . . Providers are in the business of making a living, and according to a recent story in Kaiser Health News (KHN), some hospitals are offering reduced-rate CT scans for smokers to check for lung cancers in an effort to catch cancers while they might still be curable. The Aug. 16 story states that the idea gained ground thanks to the results of a study published in June indicating that low-dose helical CT scans cut lung cancer mortality by 20% in a study that randomized more than 54,000 heavy smokers between the ages of 55 and 74 to spiral CT or standard chest X-rays. The study, which spanned nearly 10 years, suggested that spiral CT cut down on fatalities, with 354 lung cancer deaths among those with CT screening compared to 442 among patients checked with X-rays. The KHN story notes that St. Luke's Hospital (Bethlehem, Pennsylvania) had distributed a single-page flyer featuring a headline boasting that a “10-second scan could be life-saving“ along with a coupon for the procedure for $49. St. Luke's has a lot of company in this endeavor, the KHN article says, naming the University of Pittsburgh Medical Center (Pittsburgh, Pennsylvania), and the Swedish Medical Center (Denver) as others who have jumped on the bandwagon. The Kaiser article quotes William Burfeind, MD, a surgeon at St. Luke's, as saying that most of his patients “show up with stage 3 or 4 which is treatable, but rarely curable,“ adding that upon hearing the study outcomes, “we felt compelled to offer this to our patients.“ While the risk of false positives is not negligible thanks to the procedural risk of biopsy, the economics of this idea are not necessarily fool-proof, the KHN story notes, because “the results of the study suggest that more than 300 heavy smokers will need to be screened to prevent just one death from lung cancer over a five-year period.“ Peter Bach, MD, a researcher at Memorial Sloan-Kettering Cancer Center (New York) is quoted in the story as saying “it is troubling behavior,“ given the possible underlying profit motive. Still, more than 150,000 Americans die from lung cancer each year, suggesting that demand will continue to feed the supply of spiral CT capacity for some time to come
Researchers at Stanford eye dual attack on tumor angiogenesis . . . A tumor's blood supply is still a popular vector for erasing solid cancers, and an Aug. 8 statement at the website for Stanford University (Stanford, California) indicates that researchers there are examining a protein that may be able to choke off the capillaries from two angles and thus starve tumors. The statement notes that this effort found its way into publication in the Aug. 8 online edition of the Proceedings of the National Academy of Sciences in a paper that describes the development of a novel engineered protein characterized as being “significantly more effective at preventing the formation of blood vessels“ than other approaches. According to the abstract of the article, which is titled “Antagonistic VEGF variants engineered to simultaneously bind to and inhibit VEGF receptor-2 (VEGFR2) and avß3 integrin,“ scientists have noticed “significant cross-talk“ between VEGFR2 and avß3 integrin, which suggests a multiplier effect for any drug that hits them both. The researchers used an antagonistic VEGF ligand to build a molecular scaffold to deliver the dual-specific proteins that bind to VEGFR2 and avß3 integrin, and found that their engineered molecule “inhibited angiogenic processes in vitro and in vivo.“ This molecule, however, behaved very specifically to these two entities. Beyond this specific therapeutic molecule, Cochran said the scaffolding approach may work for a series of multifunctional proteins for other applications, including diagnostics, immunotherapy and tissue repair. Cochran, the statement notes, said, “this is a major advantage of two-in-one molecules.“ She cited the possibility of “a single FDA-approval process [which] could possibly shave years off the development process.“
– Compiled by Mark McCarty, MDD Washington Editor