Id helix-loop-helix proteins are differentially expressed in gestational trophoblastic disease.
OBJECTIVE
To assess the expression of Id proteins in trophoblastic tissues and to correlate this with clinical parameters, proliferative and apoptotic indices as well as to related oncogene expression.


RESULTS
Immunohistochemistry for Id1, Id2, Id3 and Id4 was performed on 83 trophoblastic tissues including 17 normal first-trimester placentas, seven term placentas, 47 hydatidiform moles (HM), and 12 spontaneous miscarriages. The four Id proteins were predominantly expressed in the villous and implantation site intermediate trophoblast. Expression of Id1 in HM was significantly higher than that in normal placenta (P = 0.0006) and spontaneous miscarriage (P = 0.0001) but did not correlate with subsequent development of gestational trophoblastic neoplasia (GTN). Id1 expression correlated with the proliferation index as assessed by MCM7 (P = 0.003) and Ki67 (P = 0.017) and with the apoptotic activity assessed by TUNEL (P = 0.001) and M30 CytoDeath antibody (P = 0.013). Moreover, the expression of Id1 correlated with the expression of p53 (P = 0.004), p21(WAF1) (/CIP1) (P = 0.003) but not with p16 (P = 0.107).


CONCLUSIONS
Id proteins may play a role in the regulation of proliferative and apoptotic activity in trophoblastic tissue and are potentially useful in differentiating molar and non-molar gestation, but are not helpful in predicting GTN.
Xue
W C
WC
Department of Pathology, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China.
Feng
H C
HC
Chan
K Y K
KY
Chiu
P M
PM
Ngan
H Y S
HY
Khoo
U S
US
Tsao
S W
SW
Chan
K W
KW
Cheung
A N Y
AN
D018797:Cell Cycle Proteins / Q000032:analysis; D050759:Cyclin-Dependent Kinase Inhibitor p21; D005260:Female; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D006828:Hydatidiform Mole / Q000378:metabolism / Q000473:pathology*; D007150:Immunohistochemistry; D051798:Inhibitor of Differentiation Protein 1; D010920:Placenta / Q000737:chemistry; D011247:Pregnancy; D012097:Repressor Proteins / Q000096:biosynthesis*; D014157:Transcription Factors / Q000096:biosynthesis*; D014327:Trophoblasts / Q000737:chemistry / Q000473:pathology; D016159:Tumor Suppressor Protein p53 / Q000032:analysis
C493956:CDKN1A protein, human; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; C497453:ID1 protein, human; D051798:Inhibitor of Differentiation Protein 1; D012097:Repressor Proteins; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53