The MGH team used the automated system to analyze CTCs from two groups of prostate cancer patients. After the cells were initially captured on the CTC-chip, which is covered with microscopic posts coated with antibody to a common tumor protein, the cells were tagged using an antibody to prostate-specific antigen, allowing rapid scanning and more comprehensive visualization of the CTCs. Samples taken from a group of men with localized prostate cancer right before and at several intervals after surgical removal showed that, while CTCs disappeared immediately after surgery in some patients, CTC levels dropped only modestly in others. Analyzing CTCs from a group of patients being treated for metastatic prostate cancer revealed that, among patients whose tumors were responding to treatment, only a few CTCs displayed a marker found on proliferating cells. But in patients whose tumors were not responding, the majority of CTCs displayed the proliferation marker.

"Further studies are needed to determine whether the differences seen in our study actually reflect which tumors are more invasive, in the case of the persistance/disappearance observation, or reveal important biological properties of the tumor," says Stott, who is a research fellow in Surgery at Harvard Medical School. "We are also working to create a 'plug-and-play' version of the machine that will be easy to use clinically, exploring options for large-scale production of the CTC-chip, and continuing to optimize the device to increase its speed and efficiency."

Source: Massachusetts General Hospital