CA-125 and HE4 levels were both increased in only 58% of serum samples of early stage serous carcinoma patients as measured by ELISA. CA-125 (A) and HE4 (B) production was measured by ELISA. Levels of these proteins were calculated as averages of triplicates. The line across the figures is the low threshold for protein up-regulation. An asterisk (*) indicates that this particular patient demonstrated no up-regulation in both CA-125 and HE4.