Comparing FPKM/RPKM between two different datasets

Question

[Aleksandar]

Hello everyone :)!

Imagine I am looking at two papers: 1) The first one performs RNA-seq on HeLa cells and then reports gene expression in FPKM. 2) The second paper does the same, but for HEK cells.

Is there any reasonable way to compare expression of genes between these two papers/datasets. Is it as straightforward as to say that 500 FPKM of the actin gene in HeLa and 250 FPKM of the actin gene in HEK -> then HeLa cells have twice the amount of RNA transcripts of the actin gene? Perhaps, there is a completely other way of comparing these or maybe it's impossible?

Thanks for the information - it is of tremendous help :)!