How to determine PSMA levels in tissue? 

Determining Prostate-Specific Membrane Antigen (PSMA) levels in tissue involves various methodologies, each with its unique approach and application, as evidenced by recent research. Immunohistochemical techniques have been traditionally used to demonstrate PSMA expression in normal and diseased prostatic tissues, offering a qualitative and semi-quantitative measure of PSMA levels. This method's sensitivity and specificity have been further validated, showing that PSMA is highly specific for prostatic adenocarcinoma, despite its expression in subsets of various malignancies. For a more quantitative approach, a dual monoclonal antibody sandwich assay has been developed, capable of detecting PSMA at sensitivities below 1 ng/mL. This assay quantifies PSMA levels in tissue homogenates and physiological fluids, providing a more precise measurement than immunohistochemical techniques. Additionally, radioligand binding assays on fresh-frozen ex vivo human tissues have been employed to determine absolute expression of PSMA, offering insights into the binding characteristics of novel radioligands and guiding imaging and theranostic strategies. Recent advancements have also introduced the use of liquid biopsy assays to detect PSMA expression on circulating tumor cells (CTCs), which could serve as a non-invasive alternative to traditional tissue biopsies. This method has shown high sensitivity, specificity, and overall accuracy in detecting PSMA expression in CTCs from metastatic castration-resistant prostate cancer (mCRPC) patient samples. Moreover, preclinical studies have utilized in vitro cell uptake studies and in vivo biodistribution and SPECT/CT imaging studies to evaluate PSMA radioligands, highlighting the importance of the tumor model and ligand amount in characterizing PSMA radioligands. These studies underscore the complexity and heterogeneity of PSMA expression across different prostate cancer models and the need for standardized preclinical study designs. In summary, determining PSMA levels in tissue can be achieved through a variety of methods, including immunohistochemical techniques, dual monoclonal antibody sandwich assays, radioligand binding assays, and liquid biopsy assays for CTCs. Each method offers unique advantages and potential applications in the diagnosis, treatment, and monitoring of prostate cancer.

Prostate-specific membrane antigen (psma) as diagnostic biomarker in prostate cancer

PSMA levels in tissue can be determined using polymerase chain reaction (PCR) to examine PSMA gene expression, as shown in the study comparing benign and malignant prostate tissue samples.

Detection and characterization of the prostate-specific membrane antigen (PSMA) in tissue extracts and body fluids.

PSMA levels in tissue can be determined using Western blot analysis, detecting 120 and 200 kDa bands in normal, benign, and malignant prostate tissues, as well as seminal plasma.

Prostate‐specific membrane antigen (PSMA) protein expression in normal and neoplastic tissues and its sensitivity and specificity in prostate adenocarcinoma: an immunohistochemical study using mutiple tumour tissue microarray technique

PSMA levels in tissue are determined using immunohistochemistry with a monoclonal antibody. PSMA expression is cytoplasmic in various tissues, aiding in distinguishing prostate adenocarcinoma with high specificity.

Impact of the mouse model and molar amount of injected ligand on the tissue distribution profile of PSMA radioligands.

PSMA levels in tissue can be determined by evaluating radioligand uptake in PSMA-expressing cells using varying molar concentrations of PSMA radioligands, as shown in preclinical studies.

A dual-monoclonal sandwich assay for prostate-specific membrane antigen: levels in tissues, seminal fluid and urine.

A dual-monoclonal sandwich assay quantifies PSMA levels in tissues by capturing the antigen with one mAb and detecting it with another, achieving sensitivity below 1 ng/mL.

Heterogeneous PSMA expression on circulating tumor cells: a potential basis for stratification and monitoring of PSMA-directed therapies in prostate cancer.

PSMA levels in tissue can be determined using Western blot, immunohistochemistry (IHC), immunocytochemistry (ICC), and FACS methods as outlined in the study.

Quantification of PSMA expression in primary human and xenograft tumors using radioligand binding and digital autoradiograpy

PSMA levels in tissue can be determined using radioligand binding assays on fresh-frozen samples, allowing for absolute quantification of PSMA expression in human prostate tumors and xenograft models.

Performance of a blood-based liquid biopsy test to detect PSMA expression on circulating tumor cells in men with metastatic prostate cancer.

PSMA levels in tissue can be determined using a blood-based liquid biopsy assay to detect PSMA expression on circulating tumor cells, as described in the study.

Determination of pharmacokinetics and tissue distribution of a novel lutetium-labeled PSMA-targeted ligand, 177Lu-DOTA-PSMA-GUL, in rats by using LC–MS/MS

PSMA levels in tissue can be determined by developing a sensitive LC-MS/MS assay for a lutetium-labeled PSMA-targeted ligand, as shown in the study on 177Lu-DOTA-PSMA-GUL in rats.

Impact of the molar activity and PSMA expression level on [18F]AlF-PSMA-11 uptake in prostate cancer.

PSMA levels in tissue can be determined through western blot and immunohistochemical assessment, detecting expression variations in prostate cancer xenografts with different PSMA levels.