BACKGROUND: Tumor interstitial fluid (TIF) rather than plasma should be used in @entity5 biomarker discovery because of the anticipated higher concentration of locally produced proteins in the @entity5 microenvironment. Nevertheless, the actual TIF-to-plasma gradient of @entity5 specific proteins has not been quantified. We present the proof-of-concept for the quantification of the postulated gradient between TIF and plasma. METHODS: TIF was collected by centrifugation from serous (n  =  19), endometrioid (n  =  9) and clear cell (n  =  3) @entity43 with early (n  =  15) and late stage (n  =  16) disease in grades 1 (n  =  2), 2 (n  =  8) and 3 (n  =  17), and ELISA was used for the determination of @entity10224 , @entity1096 and @entity7 . RESULTS: All three markers were significantly up-regulated in TIF compared with plasma (p  <  0.0001). The TIF-to-plasma ratio of the @entity43 biomarker @entity10224 ranged from 1.4 to 24,300 (median  =  194) and was inversely correlated to stage (p  =  0.0006). The @entity5 related @entity1096 and @entity7 had TIF-to-plasma ratios ranging from 1 to 62 (median  =  15) and 2 to 1040 (median  =  59), respectively. The ratios were not affected by @entity5 stage, indicative of more widespread protein expression. CONCLUSION: We present absolute quantitative data on the TIF-to-plasma gradient of selected proteins in the @entity5 microenvironment, and demonstrate a substantial and stage dependent gradient for @entity10224 between TIF and plasma, suggesting a relation between total @entity5 burden and tissue-to-plasma gradient. GENERAL SIGNIFICANCE: We present novel quantitative data on biomarker concentration in the @entity5 microenvironment, and a new strategy for biomarker selection, applicable in future biomarker studies.

Quantification of the concentration gradient of biomarkers between XXXX interstitial fluid and blood.

@entity43 :: ('MESH:D010051', 'Disease') :: ['ovarian carcinomas', 'ovarian cancer'] @entity7 :: ('7422', 'Gene') :: ['VEGF-A'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor', 'cancer'] @entity1096 :: ('6696', 'Gene') :: ['osteopontin'] @entity10224 :: ('94025', 'Gene') :: ['CA-125']
@entity43 :: (MESH:D010051,Disease) :: ['ovarian carcinoma']
