VPAC receptors were targeted with a specific fluorescent peptide, TP4303, developed in our laboratory. With an Institutional Review Board exempt approval of use of de-identified discarded samples, an aliquot of urine collected as a standard of care, from patients presenting to the urology clinic (207 patients, 176 men and 31 women, aged =21 years) was cytospun. The cells were fixed and treated with TP4303 and 4,6-diamidino-2-phenylindole (DAPI). The cells were then observed under a microscope and cells with TP4303 orange fluorescence around the blue (DAPI) nucleus were considered ‘malignant’ and those only with a blue nucleus were regarded as ‘normal’. VPAC presence was validated using receptor blocking assay and cell malignancy was confirmed by prostate cancer gene profile examination. The urine specimens were labelled only with gender and presenting diagnosis, with no personal health identifiers or other clinical data. The assay detected VPAC positive cells in 98.6% of the men with a prostate cancer diagnosis (141), and none of the 10 men with benign prostatic hyperplasia. Of the 56 ‘normal’ patients, 62.5% (35 patients, 10 men and 25 women) were negative for VPAC cells; 19.6% (11, 11 men and no women) had VPAC positive cells; and 17.8% (10, four men and six women) were uninterpretable due to excessive crystals in the urine. Although data are limited, the sensitivity of the assay was 99.3% with a confidence interval (CI) of 96.1–100% and the specificity was 100% with a CI of 69.2–100%. Receptor blocking assay and fluorescence-activated cell sorting (FACS) analyses demonstrated the presence of VPAC receptors and gene profiling examinations confirmed that the cells expressing VPAC receptors were malignant prostate cancer cells.