Early-onset breast cancer: A look from molecular biology

Abstract

Breast cancer is the most common invasive cancer in women, affecting one in 8 women throughout their lives, furthermore, it represents the leading cause of cancer death in women worldwide. Young women represent only 3% of all diagnosed cases; however, these patients have larger tumors and a higher proliferation index compared to older women. Similarly, in early-onset breast cancer, more aggressive histological and molecular subtypes with a worse prognosis are overexpressed.

In general, breast cancer in young women is related to a more aggressive tumor biology and worse clinical evolution. Basal-type and HER2-positive tumors are more frequently diagnosed in young women with breast cancer in 34.3% and 22% respectively, lymph node metastasis, multifocal disease and high tumor grade are described more frequently, compared to older population. They are generally diagnosed in an advanced stage. All of these characteristics act as poor prognostic factors, increasing the mortality rate up to 1.5 times and a higher recurrence rate compared to older patients.

In studies that analyze the gene expression of tumors in the group of young patients, identifying up to 63 genes that specifically appear altered, through which the molecular pathways that are affected can be studied, being specific oncogenic alterations and different from those that promote tumorigenesis in older patients.

Keywords: Early onset cancer, Genetic mutations, Molecular pathways