Bringing a Fresh Eye to Research
David Yao: Honing in on Kidney Cancer
David Yao says he grew up asking the question “why?” Instead of reading his textbooks, the Boston University medical student says, “I wanted to be writing them.” Yao’s curiosity led him to study the birdsongs of European starlings as an undergraduate at Johns Hopkins University. He studied neuroscience because of his own interest; economics so that he could have something to discuss with his parents during visits home; and developmental biology, axonal guidance, and Alzheimer’s disease after his grandfather developed the condition.
After entering medical school at BUMC, Yao was attracted to the field of urology and approached urologist Louis Liou. “During David’s clinical rotation, he operated with me and was enthusiastic and hard-working,” Liou says. Yao then suggested doing research with his mentor, and as Liou says, Yao had both the motivation and experience necessary to conduct medical research. “I gave him control over a project on kidney cancer, and he just took the ball and ran with it. He was very productive.”
 Yao says he knew that kidney cancer was a very bad condition and hoped to find a novel method to find and treat the cancer. “There are no good screening tools, and once the cancer spreads from the kidney there are no good treatments.” The type of cancer that Yao studied, clear cell renal cell carcinoma (CCRCC), is difficult to treat because it is resistant to chemotherapy, radiation, and immunotherapy.
Liou’s lab screened healthy and cancerous tissue from CCRCC patients using a DNA microarray of all human genes. Nearly a thousand genes were expressed differently in normal and cancerous cells, but a literature search narrowed the field to four probable candidates. “I was attracted to one gene in particular for the vitamin-D receptor (VDR), which is known to play a role in breast, colorectal, and parathyroid cancer,” Yao says. Also, low levels of vitamin D in the body are associated with obesity, a risk factor for kidney cancer. The microarray data was confirmed using a technique called quantitative Polymerase Chain Reaction (PCR). It was found that the levels of VDR mRNA were lower in cancerous cells compared to normal ones. Yao then stained both tissue types for protein expression and observed less staining in the undifferentiated, unstructured tumor cells.
If VDR levels found in serum and urine can be correlated with a particular stage of cancer, the test may form a basis for CCRCC diagnosis and prognosis. If future work with VDR vaccines or viral transfection of cells with VDR is successful, it may lead to CCRCC therapeutics. Liou says, “David’s work is a great contribution to the high-quality, groundbreaking research at Boston University.”
This research was presented as an abstract at the American Association for Cancer Research meeting in April 2006.
—by Leah Eisenstadt |
