Related Experiment Video
Updated: Jul 28, 2025
Testing Targeted Therapies in Cancer using Structural DNA Alteration Analysis and Patient-Derived Xenografts
Published on: July 25, 2020
Case report: Neuroendocrine breast carcinoma with a germline EGFR T790M mutation
Olivia A Sagan1, Anna Rothstein1, Bhaghyasree Jambunathan1
1The University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States.
Background:
The epidermal growth factor receptor (EGFR) p.Thr790Met (T790M) mutation was discovered as a resistance mechanism in patients with lung cancer treated with first- and second-generation tyrosine kinase inhibitors. Further studies revealed the EGFR T790M mutation in treatment-naive non-small cell lung carcinoma (NSCLC) and as a rare germline mutation strongly associated with NSCLC. Somatic EGFR T790M mutations have been reported in a limited population of patients with triple-negative breast cancer. There are no previous reports of a germline EGFR T790M mutation found in a patient with breast cancer.
Case Presentation:
We present a rare case of a 42-year-old woman with a rapidly progressing 8 cm mass in the right lateral breast. An additional right breast mass with multiple lymph nodes characteristic or suspicious of metastasis was found. Ultrasound-guided biopsy showed high-grade, poorly differentiated invasive neuroendocrine carcinoma of the right breast and metastatic carcinoma of a right axillary lymph node. Genetic testing revealed a germline EGFR T790M mutation. The patient underwent neoadjuvant chemotherapy, right mastectomy with lymph node dissection, adjuvant radiation to the right chest wall and axilla, and adjuvant chemotherapy.
Conclusion:
This is the first reported case of a patient with high-grade neuroendocrine carcinoma, triple-negative breast cancer and a germline EGFR T790M mutation. Further investigation is needed to find a possible correlation between the cancer in this patient and her mutation. Since there are no current guidelines, further research is also needed to define screening protocols for patients with germline EGFR T790M mutations. Additional treatment options and cancer risk could also be found with further research, which would benefit all patients with a germline EGFR T790M mutation.
Insights
This study reports the first case of high-grade neuroendocrine breast cancer with a germline epidermal growth factor receptor (EGFR) T790M mutation. Further research is needed to understand the correlation and establish screening protocols for this rare mutation.
Area of Science:
- Oncology
- Genetics
- Cancer Research
Background:
- The epidermal growth factor receptor (EGFR) T790M mutation is known as a resistance mechanism in lung cancer and a rare germline mutation associated with non-small cell lung carcinoma (NSCLC).
- Somatic EGFR T790M mutations have been identified in a subset of triple-negative breast cancer patients.
- No prior reports exist of a germline EGFR T790M mutation in breast cancer patients.
Observation:
- A 42-year-old woman presented with a rapidly progressing 8 cm right breast mass and metastatic axillary lymph nodes.
- Biopsy revealed high-grade, poorly differentiated invasive neuroendocrine carcinoma of the breast and metastatic carcinoma.
- Genetic testing identified a germline EGFR T790M mutation in the patient.
Findings:
- This case represents the first documented instance of high-grade neuroendocrine carcinoma, triple-negative breast cancer, and a germline EGFR T790M mutation co-occurring.
- The patient received neoadjuvant chemotherapy, mastectomy with lymph node dissection, adjuvant radiation, and adjuvant chemotherapy.
Implications:
- Further investigation is warranted to explore a potential correlation between the neuroendocrine breast cancer and the germline EGFR T790M mutation.
- The absence of current guidelines highlights the need for research to establish screening protocols for individuals with germline EGFR T790M mutations.
- Additional research may uncover novel treatment strategies and a clearer understanding of cancer risk associated with this mutation, benefiting a broader patient population.
