A biomarker is not necessarily one single smoking gun that tells a doctor a disease is on its way. Biomarkers are sometimes a series of changes undergone inside the body, and the challenge for researchers is to learn what those changes are and how to read them. This approach is sometimes known as "systems biology," which is what researcher Christopher Kemp used to find signs of HER2-positive breast cancer long before it could be detected in the clinic.
In experiments on mice, Kemp and colleagues found that in the very earliest stages of breast cancer, tumor cells go on a recruiting drive to convert normal tissue to the cancer cause by sending out signals. In turn, the host tissues answer back and amplify these signals.
"It is really a 'systems biology' study of cancer, in that we simultaneously examined many genes and proteins over time--not just in the tumor but in blood and host tissues," Kemp tells Drug Discovery & Development. "The overall surprising thing we found was the degree to which the host responds to cancer early in the course of disease progression, and the extent of that response. While a mouse--or presumably a human--with early-stage cancer may appear normal, our study shows that there are many changes occurring long before the disease can be detected clinically."
Kemp found a "treasure trove" of proteins involved in a variety of ways in early cancer growth. The next step is to choose the most promising protein candidates in mice and see if they are early markers for breast cancer in humans.