This is a minimal risk correlative clinical blood-drawing protocol. The objective of this lead in pilot component is to determine whether Circulating Tumor Cells (CTC's) can be captured using the novel mesenchymal-marker based Near Infrared-Emissive Polymersomes (NIR-EPs), the PSMA-based NIR-EP, and the epithelial EpCAM-based NIR-EP. If successful, the capture method will be evaluated further in the larger comparative study.

Inclusion Criteria:

• histologically confirmed diagnosis of adenocarcinoma of the prostate

• Clinical or radiographic evidence of metastatic disease

• Evidence of disease progression on androgen deprivation therapy (ADT) as evidenced by either of the following in the past:

  1. Two consecutive PSA levels greater than the PSA nadir achieved on ADT, separated by greater than one week
  2. Radiographic evidence of disease progression as defined by new bone scan lesions or soft tissue/visceral metastases >2 cm in diameter.
  3. Clinical progression as determined by the treating physician.

• Age greater than 18 years.

• Ability to understand and the willingness to sign a written informed consent document

Exclusion Criteria:

• History of intercurrent or past medical or psychiatric illness that would make participation in a blood drawing protocol difficult or not feasible at the discretion of the principal investigator or co-investigator(s)