Evaluation of miRNA 34a Expression and its Relationship to molecular Subclassification with Androgen Receptor Status in a Prognosis of Breast Cancer Patients of Pakistan

Abstract

Objective: The goal of our research was to determine the differential expression of miRNA 34a in breast cancer based on molecular subtypes and its relationship to other receptors.

Methodology: It was a retrospective study. The study included a total of 32 samples from the Islamabad Diagnostic Centre (IDC) and 4 samples of fibroadenoma, which were formalin fixed paraffin embedded tissue samples of clinically diagnosed breast cancer females for the past 5 years from University of Health Sciences (UHS). 5m tissue sections were cut for immunohistochemistry, and 20m sections for miRNA analysis were transported to laboratory, where they were stored at room temperature until further processing. Females who eligible for the study and had histologically diagnosed cases of breast cancer and fibroadenoma were included, but clinical history was excluded.  As a control, we used 32 FFPE samples of breast cancer and 4 fibroadenoma samples. Luminal A made up 51% of the 32 cases tested for molecular subtyping for breast cancer heterogeneity; whereas 40% were triple negative and 9% had the HER-2/Nueenriched aggressive type clinically.

Results: 97% of invasive ductal carcinoma samples and 25% fibroadenoma samples were negative for androgen receptors. MiRNA34a analysis shows predominant down regulation in all molecular subtypes, 3 fibroadenoma samples were also downregulated. The sample with negative androgen receptors has shown normal value of miRNA 34a.

Conclusion: As a consequence, miRNA 34a can be used as a prognostic marker for assessing the progression of breast cancer, and future studies with bigger sample sizes on other types of breast cancer could be included to make a final conclusion and set a standard for miRNA research.