Microarrays pave the way to 21st century medicine.

As CGAP carves out the foundation for a new era of molecular diagnostics in cancer, many already have begun thinking about the next steps. Klausner said recently, "You have to have the white pages [a complete index of expressed cancer genes]. But you also need the yellow pages to access, read, and coordinate what's in the white pages." Until then, cancer researchers should expect over the next few years to spend much of their time clicking through the white pages of the CGAP database. As Edward Harlow, Ph.D., chief of NCI's Office of Science Policy, said, "The CGAP is very much an idea to try and bring to all researchers access to a complete rundown of expressed sequences in common human cancers and try to get them into everybody's hands."