PSMA Expression in Solid Tumors beyond the Prostate Gland: Ready for Theranostic Applications?

In the past decades, the expanding use of prostate-specific membrane antigen (PSMA) imaging for prostate cancer has led to the incidental detection of a lot of extra-prostatic malignancies showing an increased uptake of PSMA. Due to these incidental findings, the increasing amount of immunohistochemistry studies and the deeper knowledge of the mechanisms of expression of this antigen, it is now clear that PSMA is a misnomer, since it is not specific to the prostate gland. Nevertheless, this lack of specificity could represent an interesting opportunity to bring new insights on the biology of PSMA and its sites of expression to image and treat new conditions, particularly several cancers. In this review, we will describe the main extra-prostatic cancers that exhibit PSMA expression and that can be studied with PSMA-based positron emission tomography-computed tomography (PET/CT) as an additional or alternative tool to conventional imaging. In particular, we will focus on cancers in which a radioligand therapy with (177)lutetium has been attempted, aiming to provide an overview of the possible future theragnostic applications of PSMA.

Automated summary

The expanding use of PSMA imaging for prostate cancer has led to the incidental detection of extra-prostatic malignancies. Despite the lack of specificity to the prostate gland, this presents an opportunity to gain new insights into the biology of PSMA and its sites of expression, particularly in cancer imaging and treatment.