In vitro effects of phthalate esters in human myometrial and leiomyoma cells and increased urinary level of phthalate metabolite in women with uterine leiomyoma.

OBJECTIVE: To investigate the possible role of phthalate, a ubiquitous chemical used in consumer products, in the pathogenesis of uterine leiomyoma.

DESIGN: Experimental and prospective case-control study using human samples.

SETTING: University hospital.

PATIENT(S): Fifty-three women with histologic evidence of uterine leiomyoma and 33 surgical controls without leiomyoma.

INTERVENTION(S): Human myometrial and leiomyoma cells were treated with di-(2-thylhexyl)-phthalate (DEHP).

MAIN OUTCOME MEASURE(S): Cell viability assay and Western blot analyses after in vitro DEHP treatment; high-performance liquid chromatography electrospray ionization tandem mass spectrometry in cases and controls.

RESULT(S): In vitro treatment with DEHP led to an increased viability and increased expressions of proliferating cell nuclear antigen, B-cell lymphoma 2 protein, and type I collagen in myometrial and leiomyoma cells. The urinary concentration of mono-(2-ethyl-5-carboxypentyl) phthalate was higher in women with leiomyoma compared with controls.

CONCLUSION(S): These findings suggest that exposure to phthalate may play a role in the pathogenesis of uterine leiomyoma by enhancing proliferative activity, exerting an antiapoptotic effect, and increasing collagen contents in myometrial and leiomyoma cells.