Fig. 4.

Assessment of potential biomarkers for differential diagnosis of primary versus metastatic ovarian cancer carcinoma. (a) through (c) Calreticulin protein levels were detected in cell supernatants and media controls using quantitative immunoblotting (a) and the RSI detection system. (b) Relative protein levels were calculated for measurements obtained from both systems, (c) showing high concordance between the two systems. (d) through (f) The same analyses were performed for collagen type 1. Collagen showed larger variation than the other antibodies used in the present study, which may be the result of nonspecific antibody binding to other targets as evident by nonspecific bands (data not shown). (g) through (i) Apolipoprotein A1 protein levels were quantified using both approaches. As corroborated by both approaches, apolipoprotein A1 levels were much higher than in media control in TOV-112D cells, yet much lower in SK-OV-3 cells, making apolipoprotein A1 a prime candidate for future protein biomarker panels for the differential diagnosis of primary versus metastatic ovarian carcinoma.