What happened, in summary

A 56-year-old woman presented in March 2020 with a hard mass in the outer part of her right breast. Imaging showed a lesion a little over 2 cm, and a needle biopsy confirmed invasive breast cancer. BRCA1 and BRCA2 testing did not identify pathogenic variants.

On April 3, 2020, she underwent breast-conserving surgery with a sentinel lymph node biopsy. Final pathology showed a 2.5 cm grade 3 invasive carcinoma. The tumor was estrogen-receptor negative, progesterone-receptor negative, and HER2 1+, consistent with triple-negative breast cancer.

Her family history was striking: several female relatives had developed breast cancer, and another affected family member also had triple-negative disease. Whole-exome sequencing identified a rare MT1E c.G107A (p.C36Y) variant in the two affected family members who were tested, while an unaffected relative did not carry it. The study described this as a potentially important familial finding, but further research is needed to establish its role in breast-cancer risk.