They say that prostate cancer can be detected by using its exosomes, but

A group from Institute of Chemistry, Slovak Academy of Sciences, Bratislava, etc. has reported about a measurement using a sandwich scheme with CD63, exosomes and SNA lectin for detecting prostate cancer.

In this experment, exosomes produced by prostate cancer cells are examined as a new biomarker for detecting prostate cancer.

Comparing with exosomes produced by benign (control) cell line RWPE1 and carcinoma cell line 22Rv1, it was showen that
(1) the control exosomes mainly interacted with SNA and MAAII lectins; however, they exhibited a lower affinity than the carcinoma exosomes, and also
(2) PHA-L and PHA-E were only able to bind poorly to control-derived exosomes, while there were no interactions to carcinoma exosomes.
This result is quite reasonable because usually the signal intensity of PHA-L and PHA-E disapper with fully sialylated N-glycans suggesting that sialylation is stronger in carcinoma exsosomes than that of control exosomes.

However, blog author is skeptical about their conclusion that it is possible to perform measurements in a sandwich configuration, i.e., antibody/exosomes/lectin, because exsosmes are generally strongly sialylated and CD63 can not discriminate exsosomes produced by prostate cancer cells from other exosomes.