# Drug sensitivity (PRISM Repurposing Primary Screen) 19Q4

**URL:** <https://forum.depmap.org/t/drug-sensitivity-prism-repurposing-primary-screen-19q4/314>\
**Category:** Q&A\
**Tags:** compound-screens\
**Created:** [November 29, 2020, 7:44pm UTC](https://forum.depmap.org/t/drug-sensitivity-prism-repurposing-primary-screen-19q4/314 "2020-11-29T19:44:33Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Mirella-Evotec](https://avatars.discourse-cdn.com/v4/letter/m/4491bb/32.png) [@Mirella-Evotec](https://forum.depmap.org/u/Mirella-Evotec)\
**Post date:** [November 29, 2020, 7:44pm UTC](https://forum.depmap.org/t/drug-sensitivity-prism-repurposing-primary-screen-19q4/314/1 "2020-11-29T19:44:34Z")

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Hi I’m trying to select a list of cell lines with different drug sensitivity to Olaparib using Drug sensitivity (PRISM Repurposing Primary Screen) 19Q4.  
How do we interpret the log2 fold change numbers: \< 0 is sensitive and \> 0 is resistant?  
For instance: HCC1937 cell line with a score of 0.88 is considered resistant or sensitive to olaparib?

thanks for you help  
Mirella

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**Author:** ![pmontgom](https://yyz1.discourse-cdn.com/flex035/user_avatar/forum.depmap.org/pmontgom/32/4_2.png) [@pmontgom](https://forum.depmap.org/u/pmontgom)\
**Post date:** [December 8, 2020, 3:29pm UTC](https://forum.depmap.org/t/drug-sensitivity-prism-repurposing-primary-screen-19q4/314/2 "2020-12-08T15:29:58Z")

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The more negative the value, the more sensitive. Values \> 0 suggest that the treated cells is grew more than the control cells, which often is an artifact in the assay.

Thanks,  
Phil

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**Author:** ![Gayathri](https://avatars.discourse-cdn.com/v4/letter/g/838e76/32.png) [@Gayathri](https://forum.depmap.org/u/Gayathri)\
**Post date:** [July 18, 2022, 12:12pm UTC](https://forum.depmap.org/t/drug-sensitivity-prism-repurposing-primary-screen-19q4/314/3 "2022-07-18T12:12:02Z")

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Hi,  
Thank you for this clarification.  
I could see that the log2FC is being plotted in the box plot but there is a bar chart on top of it. The X axis is log2FC but I could not find what is on the Y axis. It doesn’t seem to be the number of cell lines. Is there any way that we can know whether a particular log2FC value after drug treatment is statistically significant or not. (For eg. if Gemcitabin treated HeLa cells is having a log2FC of -0.5, how can I know if it is statistically significant.) Could you please help me out to understand this more.

Thanks for the help.