RNAi (Achilles+DRIVE+Marcotte, DEMETER2) meaning

Hello,

I want to identify HER2 positive breast cancer cell lines. I downloaded the relevant file from DepMap and created column for ERBB2 (NGL, c-ERB-2, HER-2, c-ERB2, CD340, NEU, MLN-19, p185(erbB2), HER2) using cell line selector. Additionally, I am curious about the meaning of RNAi (Achilles+DRIVE+Marcotte, DEMETER2) and how to interpret these data values. What does a data value of 0 or less mean? Can I consider cell lines with values of 0 or less as HER2 positive cell lines?

I’ll wait for your response.

Thank you.
Jaeeun