Abstract
Breast cancer commonly affects women of older age; however, in developing countries, up to 20% of breast cancer cases present in young women (younger than 40 years as defined by oncology literature). Breast cancer in young women is often defined to be aggressive in nature, usually of high histological grade at the time of diagnosis and negative for endocrine receptors with poor overall survival rate. Several researchers have attributed this aggressive nature to a hidden unique biology. However, findings in this aspect remain controversial. Thus, in this article, we aimed to review published work addressing somatic mutations, chromosome copy number variants, single nucleotide polymorphisms, differential gene expression, microRNAs and gene methylation profile of early-onset breast cancer, as well as its altered pathways resulting from those aberrations. Distinct biology behind early-onset of breast cancer was clear among estrogen receptor-positive and sporadic cases. However, further research is needed to determine and validate specific novel markers, which may help in customizing therapy for this group of patients.
Highlights
Published: 5 March 2021Breast cancer has been identified as the most common cancer among women worldwide with an estimated two million new cancer cases diagnosed in 2018, accounting for23% of all cancer types [1]
Incidence of early-onset breast cancer (EOBC) was estimated to reach 6%–10% of all breast cancer cases in developed countries; this figure doubled in developing countries where the percentage reaches 20%; the same goes for its mortality rate, that is, 7% vs. 14% for developed and developing countries, respectively [5]
We reviewed published literature addressing EOBC-related somatic mutations, chromosome copy number variants, single nucleotide polymorphism, differential gene expression profile, microRNAs, DNA methylation profile, and differentially expressed proteins, as well as altered pathways that have resulted from those aberrations
Summary
Breast cancer has been identified as the most common cancer among women worldwide with an estimated two million new cancer cases diagnosed in 2018, accounting for. Advancement in molecular technologies revealed that breast cancer is not a single disease, but is a group of conditions with distinct molecular profiles [3]. Breast cancer in young women has been defined by its aggressive nature; it tends to be of high histological grade at diagnosis, high proliferation rate, and is positive for human epidermal growth factor receptor (HER-2) and negative for endocrine receptors. EOBC has distinct biology different from that in late-onset In their view, this distinction is observed in the aggressive phenotype mentioned above, and in the different distributions of risk factors and the contradictory clinical outcome of patients with comparable clinicopathological parameters and similar therapeutic approach but the only difference is that they belong to different age groups [16,17]. We believe that better understanding of EOBC biology may help in the identification and verification of molecular markers, which is a step towards personalizing therapy for this group of patients who show insufficient efficacy to conventional adjuvant hormone and chemotherapy
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
