Clarification Regarding DepMap's IC50 Data and Sanger's IC50 Data

Hi DepMap,

I am a little confused regarding the information you have on your website and Sanger’s information. I am refering to your Drug sensitivity IC50 (Sanger GDSC1 and GDSC2) data as well as what Sanger has on their website if you go to compounds and look for a specific drug. Usually, Sanger will present a table like the following:

|Number of cell lines screened|913|
|Maximum IC50 (uM)|2.18e+3|
|Geometric mean (uM)|34.8|
|Minimum IC50 (uM)|0.151|
|Min screening concentration (uM)|0.125|
|Max screening concentration (uM)|32.0|

Maybe this is due to the fact that I need to research more information on IC50 values, but how can an IC50 value be higher than the max screening concentration? Thanks for your help.


Hi SD,

The IC50 values are typically computed as the dose that the fitted curve would reach to 50% viability value. For the cases this number falls out of the range of the measured doses it is given based on the extrapolated curve and I don’t think that is a good number to use in any analysis. I would recomment to replace it with either an NA or capping it with a multiple of the maximum measured dose (maybe 2x).