HI Devin, I think that back in the days (a couple of years ago) when an entire paper could be the results of a microarray/RNA seq experiment qPCR validation was necessary. Now a days, you can't really publish a paper on only microarray/RNA seq data and you would typically have some functional validation. For example, if your RNA seq data suggests differences in nutritional pathways you would validate by running mice in CLAMS cages or cells in a Seahorse analyzer. In other words, microarrays/RNA seq are just another experimental method in your toolbox.

I have actually never validated microarray data with qPCR and reviewers have never asked for it....but maybe I am lucky.

different question: do you validate qPCRs by Northern blot or RNA-seq ? I don't see the reason why qPCR is supposed to be superior and the gold standard - RNA-seq seems to me closer to that