In patients with deep invasion into myometrium (>50%) (n = 9) genes encoding E1-S transporters were not differentially expressed, and in high-grade tumours (n = 10), we saw 2–3-fold down-regulation of four genes; ABCG2, SLC10A6, SLC22A11 and SLC51B. Genes SLC22A11 and SLC10A6 encode uptake transporters SOAT and OAT4, respectively, where decline in expression of these uptake transporters in high-grade tumours may reduce intracellular concentrations of E1-S. This evidence concerns the gene ABCG2 and neoplasm.