Letters from the July 15, 2006, issue of Science News

People want to know

“Sharing the Health: Cells from unusual mice make others cancerfree” (SN: 5/13/06, p. 292) reported that years ago it was discovered that certain male mice eradicate cancer cells and that white blood cells from these mice make normal mice cancer resistant. It also reported that it is superpremature to look forward to clinical applications. It would seem that aggressive searches for remission of cancer in humans with the use of white blood cell transplants should be undertaken ASAP.

William J. Schindele
Thousand Oaks, Calif.

I was very surprised that I could only find two research articles in PubMed on these cancer-resistant/spontaneous-regression mice, including the original description of the mice in 2003 and the recently published article. Considering the importance of the discovery, it is remarkable that so little has been published in 3 years.

Adam Shapiro
Wellesley, Mass.

If the researchers injected the animals with cancer cells, how are they sure that the mice are resistant to cancer cells and not just superresistant to foreign cells? Wouldn’t the true test be to challenge the mice with cancer-causing chemicals and/or radiation?

Tom Harrison
Sunnyvale, Calif.

Researcher Mark Willingham of Wake Forest University answers that several pieces of evidence come to bear on this question. Many of the cancer cells lack markers of “foreignness” to the mice. The cells get a response from parts of the immune system that don’t depend on these markers. The immune response in the mice is much faster than the one geared to foreignness. The cancer resistance can be transferred to mice engineered to not have an immune response to foreign cells.—C. Brownlee

Relatively easy to take

Unlike some, I find no problem with the idea of hybrids between ancestors of chimpanzees and humans (“Hybrid-Driven Evolution: Genomes show complexity of human-chimp split,” SN: 5/20/06, p. 308). We have to assume that any speciation event will be protracted. The collection of genes that separate humans from apes would hardly have arisen in a single individual. From my study of dabbling ducks, I have come to believe that formation of hybrids is common during speciation events.

Terry Toohill
Whangarei, New Zealand