3.3 Determination of optimal cutoff values of EVI1 transcript
for patient grouping
Firstly, we used the normal threshold 8.0% as the cutoff value. As
shown in Fig. 1B, the grouped patients had similar 5-year RFS rates
(P =0.48). Next, patients were grouped into quartiles according to
EVI1 transcript levels (1st quartile to 4th quartile, from low to high
levels). Although the 5-year RFS rates were similar among the four
groups (P =0.37), there was a trend that 1st quartile patients had
lower 5-year RFS rate compared to the other 3 groups (P =0.17,
0.40, and 0.15, Fig. 1C), and the other 3 groups had the similar RFS
rate (P =0.75, Fig. 1C).
Then, the ROC curve analysis was performed to determine the optimal
cutoff value of EVI1 transcript levels. Although the EVI1 transcript
levels could not significantly differentiate patients in relapse (area
under the curve 0.57, P =0.24), 0.10% had the maximal Youden
index and was determined as the optimal cutoff values. As a result, 32
(18.2%) and 144 (81.8%) patients had EVI1 transcript levels
<0.10% and ≥0.10% and were defined as low and high EVI1
expression in our cohort, respectively.