log2(TPM+1)

Question

[Lakshmi]

Hi, I have a basic question with CCLE expression data. Why is the expression data given as log2(TPM+1) instead of log2TPM?

Thanks in advance for your help.

Answer 1

[Mensur Dlakic]

Any logarithm of zero is undefined. Adding 1 to TPM values ensures we are not attempting to take log2(0).