HSD17B4 and ovarian neoplasm: In addition, increased expression of the E1 synthetic enzymes HSD17B2, HSD17B4 and HSD17B6 in ovarian tumours is inversely associated with the probability of PPS (HR = 1.21 (1–1.45), p = 0.045; HR = 1.29 (1.07–1.55), p = 0.0073; respectively) (Figure 6D–F).