Advanced surgical cytoscopy uses antibodies to detect bladder cancer

Intraoperative cytoscopic imaging being developed at Stanford University School of Medicine uses antibodies and fluorescence to home in on a protein target called CD47 to improve surgical accuracy, the institution announced Wednesday. 

The technique can be used in real-time in resected bladder tissues during cancer surgery as an alternative to biopsy.

Researchers including Joseph Liao, MD, an associate professor of urology and chief of urology at the Veterans Affairs Palo Alto Health Care System, were inspired to use the biomarker, previously the target of a cancer therapy that targets CD47 to turn off cancer cells’ chemical cloaking device so that the immune system take them to task. Here, the researchers are aiming at that same biomarker, but this time for imaging purposes.

“Our motivation is to improve optical diagnosis of bladder cancer that can better differentiate cancer from noncancer, which is exceedingly challenging at times,” Liao said in the Stanford release. “Molecular imaging offers the possibility of real-time cancer detection at the molecular level during diagnostic cystoscopy and tumor resection.”

CD47 is expressed on the surface of cancer cells. Researchers evaluated two fluorescent tags conjugated them with fluorescein isothiocynate. This, in turn, shines when white light from confocal endomicroscopy is applied to cancer cells, whereas noncancerous cells remain the same.

Out of 119 tissue samples from 26 bladders, researchers found that the technique had about a 90.5 percent specificity and a sensitivity of about 82.9 percent.
Blue light cystoscopy also was effective using fluorescent quantum dots to create images of the offending cancer cells.