Table 2.
Determination of threshold of an antigen that discriminated recurrent ovarian cancer patients (serum was drawn close to 1 year before clinical recurrence) from non-recurrent ovarian cancer patients (serum was drawn close to 1 year after diagnosis) in the training set
| Antigen biomarker | Threshold of antigen | Sensitivity (percent reactivity of an antigen with recurrent ovarian cancer patients) | Specificity (percent non-reactivity of an antigen with non-recurrent ovarian cancer patients |
|---|---|---|---|
| Ro52 | 0.17 | 60% (3/5) | 75% (3/4)* |
| CDR2 | 0.17 | 80% (4/5) | 80% (4/5) |
| HARS | 0.03 | 40% (2/5) | 40% (2/5) |
| 4B7 | 0.03 | 20% (1/5) | 80% (4/5) |
| 4H4 | 0.03 | • | • |
| 5H6 | 0.03 | 20% (1/5) | 80% (4/5) |
| T7 1-2a (negative control) Δ | 0.03 | 20% (1/5) | 100% (5/5) |
Note:
Calculation of threshold for each antigen:
Normalized signal intensity value was calculated by dividing the background corrected signal intensity obtained with patient’s serum by background corrected signal intensity obtained from His-tag antibody
Median of normalized signal intensity value of T7 1-2a (negative control) with 5 recurrent and 5 non-recurrent ovarian cancer patients in the training set was 0.010
Standard Deviation (STDEV) of the normalized signal intensity value of T7 1-2a (negative control) with 5 recurrent and 5 non-recurrent ovarian cancer patients in the training set was 0.0173
Please note that the threshold values were adjusted to 2 places of decimal in excel worksheet (data not shown)
Threshold for HARS, 4B7, 4H4, 5H6:
(Median T7 1-2a + 1.3*STDEV)= (0.010 +1.3× 0.0173) = 0.03 (after adjusted to 2 places of decimal)
Threshold for Ro52, CDR2:
(Median T7 1-2a + 9*STDEV)= (0.010 +9× 0.0173) = 0.17 (after adjusted to 2 places of decimal)
Did not have data for 1 non-recurrent ovarian cancer patient for Ro52 protein
• Using the threshold 0.03, 4H4 did not get selected but it was still used for the test set because training set had small sample size and strict rules could not be applied.