The role of micro ribonucleic acids in predicting the invasiveness of lesions whose histopathology result as ductal carcinoma in situ in breast biopsies

Breast cancer is an important disease due to its high incidence and mortality rate. When diagnosed early, life expectancy is very high. Ductal carcinoma in situ (DCIS) is neoplastic cell proliferation, which is considered a precursor lesion of breast cancer and is not capable of metastasis yet. Recently, genetic studies have been carried out on breast cancer and gene changes in carcinogenesis steps and the effects of microRNAs on genes have been revealed. However, although the mechanisms involved in the transition from normal tissue to DCIS have been studied, no biomarker that can detect breast cancer and be used as a treatment target has been identified at this point. In our study, we aimed to evaluate the effectiveness of 11 miRNAs that are dysregulated in the transition from normal tissue to DCIS in predicting the transformation of DCIS-diagnosed lesions into invasive breast cancer. Our study included 40 female patients who applied to Bezmialem Vakif University Medical Faculty Hospital, Department of General Surgery, Breast Diseases Polyclinic, who underwent trucut breast biopsy and were diagnosed with DCIS histopathologically, and 8 female patients diagnosed with fibroadenoma as the control group. Patient groups; DCIS group (group A) and invasive carcinoma group (group B) were planned according to their pathological diagnoses after surgical excision. The FFPE (Formalin-Fixed Paraffin-Embedded) blocks of the patients were found by scanning the archives of the Department of Pathology. Total RNA and miRNA were obtained from paraffin blocks with FFPE RNA Purification Kit and then RT-PCR was used. MiR-let-7a was used as the reference gene throughout the study. The Ct values to be obtained and the increase and decrease rates of the genes were calculated using the 2-ΔΔCt method and statistical significance was accepted as p<0.05. In our study, it was observed that miR-21-5p and miR-210 were expressed statistically significantly different between the groups and the expression values increased comparatively with the degree of invasion. Clinically, these results can be helpful in early diagnosis and may help to predict if the lesions that were diagnosed as DCIS in core biopsy had invasive components. Key words: DCIS, Ductal carsinoma in situ, miRNA, Breast cancer