The difference in miR-21 expression levels between invasive and non-invasive breast cancers emphasizes its role in breast cancer invasion.
MicroRNA-21 (miR-21) overexpression is characteristic for various types of tumors, but it is still unknown whether its expression levels differ between invasive and non-invasive breast carcinomas. The main goal of the study was to determine the difference in miR-21 expression among normal tissue, non-invasive, invasive with non-invasive component, and pure invasive breast cancer samples, to explain its potential role and significance in breast cancer invasiveness. The second goal was to propose miR-21 as molecular marker of breast cancer invasiveness and potential target for future anti-miR therapies for the prevention of invasion and metastasis. In order to reveal the role of miR-21 in breast cancer invasiveness, we measured miR-21 expression levels in 44 breast cancer and four normal samples by stem-loop real-time RT-PCR using TaqMan technology. Relative expression levels of miR-21 were significantly higher in invasive than in other groups (P=0.002) and significantly higher in invasive compared with invasive with non-invasive component group in histological (P=0.043) and nuclear grade 2 (P=0.036), estrogen-receptor-positive (ER+) (P=0.006), progesterone-receptor-positive (PR+) (P=0.008), ER+PR+ (P=0.007), and proliferation index (Ki-67)≤20% (P=0.036) tumors. Our findings suggest that miR-21 could be independent molecular marker of breast cancer invasiveness and potential target for future anti-miR therapies for the prevention of invasion and metastasis.
Vinča Institute of Nuclear Sciences, University of Belgrade, Mike Petrovića Alasa 12-14, 11001, Belgrade, Serbia, dragoninspiration@yahoo.com.
Nina
N
Petrović
Vesna
V
Mandušić
Boban
B
Stanojević
Silvana
S
Lukić
Lidija
L
Todorović
Jelena
J
Roganović
Bogomir
B
Dimitrijević
D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000235:genetics* / Q000378:metabolism / Q000556:secondary; D018275:Carcinoma, Lobular / Q000235:genetics* / Q000378:metabolism / Q000556:secondary; D016022:Case-Control Studies; D005260:Female; D005500:Follow-Up Studies; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007124:Immunoenzyme Techniques; D008207:Lymphatic Metastasis; D008875:Middle Aged; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015996:Survival Rate
D012333:RNA, Messenger; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone