Lung Cancer Gene Discovery A Sign of Cancer's Future
Science is tackling gene-caused flaws, cancer stem cells, and earlier detection of tumors
Metastasis might also be foiled by immunotherapy, which prompts the body's own defenses—usually muted or silenced by cancer—into action. At the Fred Hutchinson Cancer Research Center in Seattle, researchers reported in June that an experimental treatment involving the cloning of a patient's immune cells (and injection of a superdose) apparently sent one metastatic melanoma patient into remission. The treatment didn't have the same effect on several other patients. Johns Hopkins researchers are working on therapeutic vaccines against pancreatic and breast cancers.
Seeking the Earliest Signs
Of course, metastasis and the deaths that it causes could be avoided much more handily if more cancers were easily detectable early on, as are breast, colorectal, and a small handful of other cancers. "The [number of] cancer survivors is going up because we are catching things early, before they can spread," says geneticist George Miklos, whose Sydney-based consultancy advises companies on genetics and molecular medicine.
Jane Tervooren, now 55, believes early detection saved her life. She felt for years that she was destined to get cancer; her grandmother died of ovarian cancer, and her mother did too, after surviving breast cancer. "My mother made me swear, on her deathbed, that I'd get my ovaries removed," she remembers. She did that and registered with the Family Risk Assessment Program at the Fox Chase Cancer Center in Philadelphia, where she eventually discovered she carried an inherited mutation in a gene, BRCA1, associated with ovarian and breast cancer. Because of her heightened risk, she received preventive medication that blocks estrogen production and had her breasts monitored frequently. Earlier this year, a mammogram detected very early-stage cancer, and after surgery, she's being treated with chemo.
Tervooren had her ovaries removed because there is no proven method to detect cancer in that organ early. Ovarian cancer, like other cancers, is screaming for some kind of advance in early detection. And the search is on for "biomarkers"—DNA, RNA, or proteins in the blood and other bodily fluids that indicate the presence or progress of disease in the body. In fact, says Lee Hartwell, president and director of Fred Hutchinson, the hope is that these markers will not only point out cancer early but also help characterize it, reveal whether it's responding to therapy, and indicate whether a recurrence is likely.
Researchers at Fred Hutchinson are now investigating whether the body's immune response to the earliest presence of lung cancer can be detected in the blood, much the way an HIV test searches for antibodies to the virus. Other researchers have identified a potential protein biomarker for ovarian cancer called HE4, now in use to determine how far a tumor has advanced and being studied for screening.
The challenge is not so much finding markers as it is knowing what they mean. Don Listwin, founder and chair of the Canary Foundation, a nonprofit devoted to early-detection research, points out that markers aren't very useful unless they indicate only cancer and can distinguish the lethal types from ones that aren't likely to progress.
Prostate-specific antigen, or PSA, for example, can indicate the presence of prostate cancer. But it also leads to false alarms and detects slow-growing cancers that most likely would never have caused harm. Just this month, the Food and Drug Administration chastised the manufacturer of OvaSure for marketing—without approval—the new blood test that measures the level of six proteins associated with ovarian cancer. It's not definitive, and gynecologists worry that it will lead women to have unnecessary surgery to remove their ovaries. Canary has launched a clinical study to identify biomarkers that predict the more aggressive forms of prostate cancer and is also investigating early detection of lung, pancreatic, and ovarian cancers.
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