Overexpression of laminin receptor 1 on decidual cells in partial and complete mole.

OBJECTIVES

Laminin receptor 1 (LR1), a non-integrin-type laminin receptor, has been described in several tumors and may play a role in tumor invasion. It is well known that LR1 can modify the conformation and degradation of laminin thus enhancing tumor cell invasion. LR1 may play a role in controlling trophoblast invasion in normal and molar pregnancies.

MATERIALS AND METHODS

Real-time polymerase chain reaction (RT-PCR) was performed on total cDNA from 17 gestational age-controlled normal placentas, 10 complete moles (CM), and 4 partial moles (PM). Immunolocalization of LR1 was performed on paraffin sections prepared from 17 age-controlled placentas, 17 PM, and 19 CM.

RESULTS

RT-PCR demonstrated a 13-fold increase in LR1 mRNA expression in molar tissues (PM and CM combined) versus normal placentas (p=0.012). Immunohistochemical analysis revealed LR1 localized to the decidual cells. In normal placenta LR1 localized to the decidual cell membrane. However, in PM and CM, LR1 was additionally noted in the cytoplasm of decidual cells. Interestingly, with immunohistochemistry method, we found that PM demonstrated higher protein expression of LR1 than either normal placenta or CM (p=0.001 and p=0.024, respectively).

CONCLUSION

LR1 is expressed in both the decidual cells of normal placenta and mole (CM and PM). Decidual cells in CM and PM express LR1 significantly greater than the decidual cells in placenta. The underlying mechanism of how molar tissue may be associated with enhanced expression of LR1 in the maternal endometrium is unclear.