Down-regulation of soluble fms-like tyrosine kinase 1 expression in invasive placentation.

PURPOSE: To confirm reduced expression of soluble fms-like tyrosine kinase 1 (sFlt-1) in accreta/increta.

METHODS: Formalin-fixed tissue sections from 11 peripartum hysterectomies with invasive placentation and 5 controls were stained for sFlt-1. Stain intensity was scored in selected 100× microscopic fields. We compared sFlt-1 expression in invasive areas among cases, non-invasive areas among cases and areas from control placentas.

RESULTS: Chorionic villi displayed significantly decreased sFlt-1 expression in invasive areas of cases compared to control placentas (p = 0.003), as well as in non-invasive areas of cases compared to control placentas (p = 0.01). There was no difference in sFlt-1 expression between invasive and non-invasive areas among cases.

CONCLUSIONS: Expression of sFlt-1 is diminished in villous trophoblasts from patients with placenta increta or percreta. Local depth of invasion was not associated with sFlt-1 expression, suggesting a more global abnormality across the implantation site rather than localized to areas of histologic invasion.