TMPRSS2-ERG positive VCaP cells (0, 10, 100, 1,000, 10,000, and 100,000) were incrementally spiked into 1,000,000 LNCaP cells to simulate prostate tumor tissue samples, which contain mixtures of tumor and non-malignant stroma, and 1/10 of each sample was analyzed using PRISM-SRM. This evidence concerns the gene TMPRSS2 and prostate neoplasm.