TFPI2 (tissue factor pathway inhibitor 2) expression was restricted to the placenta.
Maternal expression was observed in 4 of 8 first trimester placenta samples (8-14 weeks
gestation). The remaining 4 showed biallelic expression, suggestive of either
polymorphic imprinting or cell-type specific imprinting in a tissue
containing multiple cell types (Monk
D et al, 2008).