The observed results for the two sialyltransferases (ST8Sia and ST3Gal V) are diametrically opposed, down to the changes in ABCC1 and ABCB1 expression and the involvement of PI3K/Akt signaling pathway, which has been well established as important to drug resistance mechanisms as well as tumor proliferation (115, 124, 125). This evidence concerns the gene ABCB1 and neoplasm.