A review of Breast cancer in men and the most important microRNAs involved in this cancer

A review of Breast cancer in men and the most important microRNAs involved in this cancer
Javad Yaghmoorian Khojini,^1,* Ali Osmay Gure,²
1. department, of cellular and molecular biology and microbiology, Faculty of Biological science and technologies , University of Isfahan, Isfahan, Iran
2. Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey
Introduction: Breast cancer is a very rare disease in men. This is probably due to the smaller amount of breast tissue and the fact that men produce lower amounts of hormones such as estrogen, which have been shown to affect breast cancer in women. However, only one in 100 cases of breast cancer occurs in men, and out of one million men, only 10 people get the disease. Breast cancer is very rare for men under the age of 35, but the risk increases with age. In fact, men get the same type of breast cancer as women and which involves different profile changes in both mRNA and micro-RNA (miRNA) expression. Non-coding RNA based regulation is a newly discovered way of genome regulation which includes microRNAs, lncRNAs, siRNAs, and piRNAs. MicroRNAs or miRNAs are 21-23 nucleotide non-coding RNAs with clear function in cell division, differentiation, and apoptosis. The RNAs are responsible for post-transcriptional regulation, typically through sequence-specific interactions with 3’ untranslated region of mRNAs. In this study, breast cancer in men and the most important microRNAs involved in this cancer will be investigated.
Methods: In this study, the method of library collection, search in various texts and authoritative scientific articles has been used.
Results: Male Breast cancer (MBC) is a rare disease in men, representing less than 1% of all malignancies and responsible for 0.1% of male cancer deaths and it has a more aggressive clinical behavior compared with female breast cancer. MicroRNAs (miRNAs) are a class of small noncoding RNAs that control gene expression by targeting mRNAs and triggering either translation repression or RNA degradation. There have been many studies on the expression of various miRNAs and their roles in breast cancer. Previous studies have demonstrated that there is a large number of deregulated miRNAs in human breast cancer (in particular, miR-10b, miR-17-5p, miR-21, miR-27a, miR-27b, miR-125a, miR-336, miR-10b, miR-126, miR-125a-5p, miR-125b and the let-7 family). Studies show that miR-499-3P and miR-330-5p are among the major microRNAs in male breast cancer. Other important microRNAs that may be involved in this cancer include miR-191, miR-10b, miR-218, miR-140-3p and miR-126. Only few studies have been reported regarding miRNA expression profiling in MBC. From a histological point of view, male breast cancer is usually an invasive ductal carcinoma. This histotype specificity seems one of the major differences between male and female breast cancer biology. In this regard, some studies analyzed the miRNA expression profiles of male/female breast cancer samples, looking for miRNAs differentially expressed between the two clinical categories. Previous studies of miRNA expression in human breast cancer have focused on comparing normal tissues with tumor samples Studies show that some microRNAs, such as miR-10b, can increase the incidence of breast cancer in women by inducing tumor invasion and metastasis of breast cancer-derived cells, and this can also affect breast cancer in men. Studies show that a number of microRNAs in breast cancer are upregulated, such as miR-149 and miR-29b, and others are downregulated, such as miR-145, miR-10b, let-7g, which are being studied in laboratory studies. In the last part of this section, we will explain the most normal way to control breast cancer in men. Gynecomastia means excessive breast enlargement in men. This type of breast enlargement is mostly due to the growth of mammary glandular tissue, not much adipose tissue due to obesity. Gynecomastia could be considered a good normal control for male breast cancer. Numerous conditions have been associated with gynecomastia, but the pathophysiological bases are due to an imbalance of sex hormones and the tissue responsiveness to them.
Conclusion: MiRNAs, as mRNA regulators, could serve as novel diagnostic and prognostic candidates, and potential therapeutic targets in breath cancer. In this study, we tried to give a brief and useful study of breast cancer in men and the microRNAs involved in this cancer.
Keywords: MBC, miRNAs, Gynecomastia