Abstract
Background: According to American Cancer Society, an estimated 268,600 new cases of invasive breast cancer was diagnosed among women, and nearly 50,000 women were under age 50 years. Therefore, the identification of young age breast cancer patients can have a collosal impact on treatment, and medical follow-up. The present study aimed to understand the young age breast cancer pathophysiology and redound new BRCA variants to literature.
Methodology: This was a double-centre study performed in the Medical Genetics Department of Kahramanmaras Necip Fazıl City Hospital. In this study, sixty female patients, who are under 45 years old, diagnosed with primer breast cancer in the oncology clinic of the same hospital and Kahramanmaraş Sütçü İmam University were included. The patients were selected for BRCA mutation testing based on NCCN Guideline Version 3.2019 BRCA1/2 Testing Criteria. Relatives who meet the same criteria from the same family were not included to prevent repetition. Patients with known other cancer syndromes were also excluded.
Results: We found that Luminal-B type breast cancer was the most frequent subtype (p < 0.001), patients with Luminal-A subtype breast cancer had significantly smaller tumor size and smaller grade than those had other subtypes of breast cancer at diagnosis stage (p = 0.03 and p < 0.001, respectively). Regarding tumor localization, the breast carcinomas were mostly localized in the right breast (53.3%). Two patients (3.3%) had BRCA1
pathogenic mutation and five patients (8.3%) had BRCA2 pathogenic mutation. Additionally, we found two new variations in BRCA2 gene (c.478_488delGTATGTGGGAG and c.8830 A>T (rs4987047). All BRCA1/2 MLPA results were normal.
Conclusion: The incidence of young age breast cancer varies among countries, and it is higher in developing countries. Understanding of young age breast cancer cases will be helpful to provide suitable treatment options and will help to reduce the death rate of these patients.

Key words: Young age breast cancer, BRCA1, BRCA2