[Overexpression of high mobility group A2 and its correlation with microRNA let-7 family in serous ovarian cancers].
OBJECTIVE
To examine the expression of high mobility group A2 (HMGA2), P53 and let-7 family microRNA, to investigate the correlation of HMGA2 and let-7, and to compare the HMGA2 and P53 expressions in human serous ovarian cancer.


METHODS
Immunohistochemistry assay was used to examine the expressions of HMGA2 and P53 in 50 paraffin-embedded tissue specimens of human serous ovarian cancer and 4 normal fallopian tube tissues. HMGA2 mRNA and let-7 family microRNA were detected by real time fluorescent quantitative reverse transcription polymerase chain reaction in the corresponding frozen tissues.


RESULTS
HMGA2 and P53 were immuno-positive in 70% (35/50) and 78% (39/50) of the ovarian cancer tissues, respectively. HMGA2 was weakly expressed in the ciliated cells, but negative in the secretary cells of the fallopian tube. There was a tendency that the expression of HMGA2 increased with higher pathological grade of the ovarian cancer, but no correlation was observed between the HMGA2 overexpression and clinical stages. HMGA2 mRNA was detected in all the ovarian cancer samples, and its expression level was higher than that of the normal fallopian tube tissues in 72% (36/50) of the ovarian cancer samples. The expression of HMGA2 mRNA was much higher in more malignant SKOV3.ipl cells than in its corresponding SKOV3 cells. All let-7 family members were detectable in all ovarian cancer samples, and their expression were inversely correlated with HMGA2 mRNA expression (r=-0.305,P<0.05).


CONCLUSIONS
HMGA2 can be a biomarker complement to P53, and its high expression has an inclination of more malignancy. The downregulation of let-7 is, but not the only mechanism of HMGA2 overexpression in serous ovarian cancer.
Institute of Clinical Molecular Biology, Peking University People's Hospital, Beijing, China.
Jing
J
Yang
Qi
Q
Zhang
Jian-qiang
JQ
Dong
Xiao-hong
XH
Chang
Xiang-jun
XJ
He
D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D018284:Cystadenocarcinoma, Serous / Q000235:genetics* / Q000378:metabolism; D005260:Female; D025743:HMGA2 Protein / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D010051:Ovarian Neoplasms / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
D014408:Biomarkers, Tumor; D025743:HMGA2 Protein; D035683:MicroRNAs; D012333:RNA, Messenger; C487931:mirnlet7 microRNA, human