Cells AverageĀ  DES uptake in 1 hr* 13C fumarate in media** 13C lactate in media**
RENCA 4 % (n = 3) 1.2 ± 0.2 (+DES)
0.44 ±0.09 (-DES)
P = 0.005
9.2 ± 2.7 (+ DES)
4.7 ± 0.58 (-DES)
P = 0.05
Breast 4T1 4 % (n = 3)   2.9 ± 0.5 (+DES)
1.8 ±0.2 (-DES)
P = 0.02
Lymphoma A20 0% (n = 2)    
*The DES uptake experiments for RENCA and 4T1 cell line were highly variable from 32-22% to 0% after a one hour incubation.
**Normalized concentration of fumarate and lactate in lyophilized media after 8 hour incubation with DES (+) or without DES (-). In addition, the difference between 13C lactate (DES +) values between RENCA and 4T1 is significant (P < 0.02).
Table 3: Summary of in vitro 1,4-13C Diethyl Succinate (DES) experiments.