Early-onset breast cancer: a look from molecular biology

Abstract

Breast cancer is the most frequent invasive cancer in women, affecting one out of every 8 women during their lifetime, and it is the leading cause of cancer-related death in women worldwide. Young women represent only 3% of all diagnosed cases; however, these patients have larger tumors and a higher proliferation rate compared to older women, and early-onset breast cancer also expresses more aggressive histological and molecular subtypes with a worse prognosis. In general, breast cancer in young women is related to a more aggressive biology and a worse prognosis. Tumors are mostly aggressive and have a worse clinical course. Basal type tumors and HER2-positive cancers are most often diagnosed in young women with breast cancer. Breast cancer was 34.3% and 22%, respectively, with a higher frequency of lymph node metastasis, multifocal disease and high tumor grade, compared to the older population. They are generally diagnosed at an advanced stage. All these characteristics act as poor prognostic factors increasing the mortality rate up to 1.5 times and higher recurrence rate compared to older patients. In studies analyzing the gene expression of tumors in the group of young patients, up to 63 genes have been identified that are specifically altered, through which the molecular pathways that are affected can be studied, being specific oncogenic alterations different from those that promote tumorogenesis in older patients.