Gene study could speed kidney cancer detection

Large-scale data mining of gene networks in fruit flies has led University of Chicago researchers to a sensitive and specific diagnostic biomarker for human renal cell carcinoma.

The research team showed that the biomarker known as SPOP is produced by 99% of clear cell RCC, but not by normal kidney tissue, as reported in the Jan. 22 online edition of Science.

Physicians could use SPOP levels to confirm or rule out a diagnosis of RCC. It could also help them determine the original source of cancers that had spread to other organs from an unknown primary tumor.

“This could serve as a diagnostic tool, lead us to new drug targets, and potentially help us detect kidney cancers sooner,” said study director Kevin White, PhD. “It also confirms our strategy of using genomics and systems-level analysis of model organisms such as fruit flies to identify factors that play crucial roles in human disease.”

When the researchers ranked 150 human equivalent genes according to their impact in flies, the top candidate was a gene known as Roadkill (CG9924), the central player in a major hub of networked genes and a crucial component in the development of the nervous system. SPOP, the human equivalent, is about 80% identical to Roadkill.

When the team screened hundreds of tissue samples from 18 different tumor types, acquired from patients having surgery, they found that 85% of RCCs produced high amounts of SPOP, while normal kidney tissue was uniformly negative. Of 300 RCC samples, 77% were positive for SPOP. All normal kidney samples were negative. The researchers found that 99% of the clear cell RCC samples showed elevated SPOP.