doiSerbia

Micro RNA-21 expression levels in invasive breast carcinoma with a non-invasive component

Petrović Nina (Vinča Institute of Nuclear Sciences, Belgrade)
Jovanović-Ćupić Snežana (Vinča Institute of Nuclear Sciences, Belgrade)
Brajušković Goran (Faculty of Biology, Belgrade)
Lukić Silvana (Institute for Oncology and Radiology of Serbia, Belgrade)
Roganović Jelena (Faculty of Dentistry, Department of Pharmacology, Belgrade)
Krajnović Milena (Vinča Institute of Nuclear Sciences, Belgrade)
Mandušić Vesna (Vinča Institute of Nuclear Sciences, Belgrade)

Invasive ductal carcinomas with a non-invasive component (IDC-DCIS) are classified as a group of invasive breast carcinomas, together with pure invasive ductal carcinomas of the breast (IDC). MicroRNA-21 (miR-21) has been characterized as a factor of breast cancer invasiveness, however the difference in miR-21 expression levels between IDC-DCIS and pure IDC tumors and the correlations with standard diagnostic and prognostic parameters inside the IDC-DCIS group are unknown. Our aim was to determine if miR-21 had the ability to distinguish these two invasive breast cancer groups. Levels of miR-21 expression were measured by a stem-loop quantitative Real-Time PCR (RT-qPCR) method. Expression levels of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (Her-2) and proliferative index Ki-67 were evaluated by immunohistochemistry. IDC-DCIS tumors had significantly lower levels of miR-21 expression in grade 2 (P=0.003, Mann-Whitney U test), ER positive (P=0.025, Mann-Whitney U test) and PR positive tumors (P=0.024, Mann-Whitney U test) than pure IDCs. miR-21 levels showed a different pattern of expression in IDC-DCIS compared to IDC tumors, which is based on the difference in miR-21 expression between Her-2 negative and Her-2 positive IDC-DCIS tumors (P=0.030, Mann-Whitney U test) and high negative correlation of miR-21 levels with PR levels (ρ=-0.886, P=0.006, Spearman correlation). According to our results, IDC-DCIS breast carcinomas act in a different manner in pure IDC tumors with regard to the relations between miR-21 expression levels and the standard diagnostic and prognostic parameters, such as Her-2 status, ER and PR status and protein levels.

Keywords: Invasive ductal carcinoma with non-invasive component (IDC-DCIS), miR-21 expression levels, the difference between IDC-DCIS and IDC