Such an approach does not allow for the analysis of the expression of particular isoforms, among others, the isoform considered as the constitutional isoform of PFKFB4. Moreover, there is no possibility of examining the constitutive isoform by the RT-qPCR method, and when it comes to melanoma cells, using primers covering all six isoforms, most probably isoforms with the highest expression (D and F) significantly influence the final picture of PFKFB4 expression pattern. Here, PFKFB4 is linked to melanoma.