Anyone else have a problem with the CA drug cell cycle in FA?

[gouda]

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If bleomycin causes strand breakage and intercalates - why G2? Even considering etoposide in G2 is kind of a stretch of the imagination (I know FA says it is specific to G2, but topoisomerase is used in DNA syn...)

I have tried to make sense of this with HY mol and Harrisons but without success...if anyone can suggest an explanation/source/diagram that would lead me to enlightment, I would be much appreciative

 

[Mr. Freeze]

Since that drawing comes from a Katsung and Trevor book, I'd look there.

 

[PenguinHead]

I was wondering about etoposide also.

From NIH

The mechanism of action of etoposide is not fully understood; however, its cytotoxic effects appear to be produced by inhibiting DNA or altering DNA synthesis. Etoposide also appears to be cell-cycle dependent and cell-cycle specific, inducing G2-phase arrest and preferentially killing cells in the G2 and S phases. Although in vitro cytotoxicity of etoposide phosphate is significantly less than that produced by etoposide, once the salt form is dephosphorylated in vivo, its mechanism of action is equivalent to that of the base form.[

 

[gouda]

I checked the Katzung book, not the USMLE road map, and the image they show has no specific drugs associated with it. There is a table dividing cell specific vs non cell specific, but it does not define the stages the drugs work on...so much for trying to logically deduce the answers...