CTC analysis indicates prostate cancer severity
MedWire News: Detection of circulating tumor cells (CTCs) may form the basis of noninvasive testing for metastatic disease in early PC, researchers report.
CTCs are thought to facilitate the spread of cancer to sites such as bone, lung, brain, and liver through the bloodstream.
“No standard histological markers reliably distinguish indolent from potentially invasive prostate cancer,” report Daniel Haber, from Harvard Medical School in Boston, Massachusetts, USA, and fellow study authors.
“This method for analysis of CTCs will facilitate the application of noninvasive tumor sampling… and warrants the initiation of long-term clinical studies to test the significance of CTCs in invasive localized disease,” they add in the journal Science Translational Medicine.
The team carried out CTC analysis using blood samples from 36 metastatic prostate cancer patients, 19 patients with localized disease.
The cancer patients’ prostate-specific antigen (PSA) measurements were used as staining markers for the quantification and molecular characterization of CTCs, which were analyzed using a three-dimensional microfluidic device developed by Haber and team.
Among men with prostate cancer, CTCs were detected in 42% of patients with localized disease, and in 64% of patients with metastatic disease.
A total of 19 patients were scheduled for curative surgery, and PSA-expressing CTCs were detected in 42% of these men before surgery . The researchers used these data to calculate the half-life of CTCs, which was observed as rapid (under 24 hours) in six patients, and delayed (under 3 months) in the remaining two men.
The researchers note that this “may provide significant insight into the biology of early prostate cancer,” and that the finding suggests “early but transient disseminated tumor deposits,” after prostate removal.
Finally, the TMPRSS2-ERG gene fusion – specific to prostate cancer – was found in the RNA of the prostate CTCs, “which definitively identifies their derivation from malignant prostatic epithelial cells,” write Haber et al.
“The study of CTCs is essential to understanding the vascular spread of cancer to distant sites and for making use of these cells for real-time, noninvasive tumor monitoring,” concludes the team. They believe their results “provide a step towards the eventual clinical deployment of microfluidic CTC technologies.”
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By Sarah Guy