The AuNP adsorption assay results of serum spiked with different prostate tissue lysates. All samples were prepared by spiking 1 μL tissue lysate into 20 μL serum. All spiked samples were incubated at 4°C overnight before assay was conducted. Particle size was measured after 8 minutes of serum-AuNP incubation. A and B: the assay results of 8 serum (normal healthy donor = 4; BPH = 4) spiked with 4 prostate tissue lysates from normal, tissue with Grade 1, Grade 2, and Grade 3 prostate adenocarcinoma. The Gleason scores of the three tumor tissues are: 4(2 + 2), 5(2 + 3), and 9(5 + 4), respectively. A is the scatter-plot of all 32 samples and B is an expansion of A with 6 samples that have relatively smaller average particle sizes. Linear regression analysis of each sample set suggests that all but BPH21 sample mixes (R squared = 0.2061, p = 0.1382) had significant linear inverse correlations between the average particle size seen in the nanoparticle assay and the increasing tumor grade/staging, with goodness of fit R squared values ranging from 0.7406, p = 0.0003 for N17 to 0.9734, p < 0.0001 for BPH 23 sample sets. C and D: two sets of assay results of two different serum samples spiked with tissue lysates from normal healthy donors, BPH patients, and PCa donors. In the first set (C), PCa2 tissue lysate was spiked to the serum at two different ratios: 1:20 and 1:100 (tissue lysate:serum, v/v). Statistically significant differences were found in the assay results between the normal controls (mean 196.1 ± 11.3SD) and BPH samples (mean 183.8 ± 6.4SD; p = 0.0078, Student t-test), BPH and PCa samples (mean 158.4 ± 16.3SD; p = 0.0051, Mann-Whitney U-test), and normal and PCa samples (p < 0.0001, Student t-test).