In discussing the search for better detection of breast cancer in “Beyond Mammograms,” Nancy Shute misses one key problem: when tests become too “perfect.” As we have learned from our experience in detecting prostate cancer by testing for high levels of the prostate-specific antigen protein, finding cancers at extraordinarily early stages raises new issues. Are we now left to treat cancers that have no clinical relevance? We already often diagnose breast cancers at one to three millimeters in size. Do women with such cancers need radiation and hormone therapy for five years after a lumpectomy? Is performing a mastectomy too radical in such cases? I believe the future of cancer therapy is getting a much better grasp of the malignant potential of these tiny tumors so that we can begin separating out those individuals who can be spared the toxicity of needless treatment rather than seeking new ways to find that first malignant cell.
Joseph P. Imperato
Department of Clinical
Radiation Oncology
Northwestern University
Feinberg School of Medicine

In “Trust Me, I’m a Scientist” [Forum], Daniel T. Willingham omits one very important, and seemingly increasing, influence on people’s belief in scientists’ findings: vested interests. These usually well-financed lobbies loudly deny the validity of scientific studies and findings, proclaim the studies to be “flawed” or produce their own studies, clearly biased and done by their own hired guns, to validate their claims. This is particularly true in such sensitive areas as the environment, global warming and food safety—areas in which studies that could lead to tighter controls would cost the vested interests money.
K. A. Boriskin
Bellingham, Mass.

It struck me while reading the issue that two articles mention the use of lab animals in a careless, emotionless and, at least for me, unethical way. In Ignacio Provencio’s “The Hidden Organ in Our Eyes,” disabled lab mice are described as being bred to solve the puzzle of many mammals’ ability to adjust their schedule to night and day without vision; in “Fast Track to Vaccines,” Alan Aderem bluntly mentions that “monkeys can be deliberately infected ... in studies, whereas it is unethical to do so to humans.” I would see a clear role for the editors of Scientific American to ask authors to explain why and how many lab animals were used and what approaches were taken to reduce their suffering.
Maurice Lousberg
Sittard, the Netherlands

Jerry Adler notes in “The Growing Menace from Superweeds” that resistance to the herbicide glyphosate in weeds has become a problem. Doug Gurian-Sherman of the Union of Concerned Scientists questions where genetically engineered crops like Roundup Ready soybeans have gotten us and argues that we should return to Gregor Mendel’s conventional breeding methods for improving crops.

An expert panel convened by the National Academies recently explored Gurian-Sherman’s question. Its conclusion was that, in general, these crops have gotten us “substantial net environmental and economic benefits to U.S. farmers compared with [conventional] crops.” The panel also concluded that we could still do better—not by returning to Mendel but by developing other new crops, promoting more sustainable management and conducting additional research on the possible impacts. My own research suggests farmers valued the benefits of Roundup Ready soybeans at around three quarters of a billion dollars in 2008, even with more than half already concerned about weed resistance and with soybean growers planning to manage a third of their crop with additional herbicides.

Given the available research, my guess about the future of agriculture is that gly­phos­ate resistance will become a lesson learned and that genetically engineered crops will become increasingly important.
Terrance Hurley
Department of Applied Economics University of Minnesota

Adler’s characterization of ragweed and pigweed (Palmer amaranth) as monsters is plain silly. These plants are just doing their amazing thing: surviving. Ragweed, for one—and I am allergic—is a wonderful survivor and great colonizer of bare ground. Carl Linnaeus was not kidding when he chose the name Ambrosia for it: achene, its nutritious fruit, provides lots of calories to wildlife. So do amaranths, which have been a human food staple as well. We have known about chemical resistance since about five minutes after we started using chemicals to kill pests. (Thank you, genetic diversity!) Yet we are using the same chemicals in ever greater quantities. I say, “Go weeds!”
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