ABSTRACT Steroid sulfatase catalyzes desulfation of all 3ß-hydroxysteroid sulfates. Steroid sulfates are water-soluble storage or excretory forms of active hormones. Although cholesterol sulfate is the least soluble of the 3ß-hydroxysteroid sulfates, it can act as a detergent and can form a micelles or mixed micelle in aqueous solutions due to its amphibic nature. The sulfated form of steroid hormones, which is inactive because of failure to bind to their receptors, becomes active after desulfation by STS. X-linked ichthyosis is an inherited skin disease caused by a lack of steroid sulfatase enzyme activity. Accumulation of cholesterol sulfate in the epidermis accounts for the symptoms of this disease. XLI is diagnosed by assaying STS activity in the placenta of the patient’s mother or in lymphocytes of the patient after birth. The STS gene has been cloned, and it has been found that most XLI patients have total deletion of the STS gene. Southern blotting using full-length STS cDNA as a probe is useful for diagnosis of XLI. PCR using STS gene and ß-globin gene primers with high-performance liquid chromatography is also useful for screening for carriers of STS defects. There are two pathways for the production of estrogen: the aromatase pathway and the sulfatase pathway. Estrogen sulfate, which is biologically inactive, is converted into an active estrogen. Steroid sulfatase proteins are abundant in patients with endometrial cancer. The concentrations of estradiol in endometrial cancer tissues are higher than the levels in plasma, suggesting that endometrial cancer tissues produce estrogens in tumor tissues. The genes of enzymes associated with synthesis of steroid hormones, including human StAR protein, 3ß-HSD, P450scc, P45017a and P450arom are expressed in carcinoma cell lines. Endometrial cancer tissues synthesize the steroid hormones, that are pregnenolone, progesterone, DHEA, corticosterone and aldosterone in situ from cholesterol. Locally produced steroid hormones seem to play roles in endometrial carcinoma cells with an autocrine or paracrine action.
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