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Alexander Drilon, MD

Gregory J. Riely, MD, PhD


Genomic Landscape of Secretory Breast Carcinomas and NTRK Fusion

By: Vanessa A. Carter, BS
Posted: Wednesday, January 25, 2023

According to Tongbing Chen, MD, of the Third Affiliated Hospital of Soochow University, Changzhou, China, and colleagues, ETV6::NTRK3 gene fusion involving multiple sites may drive tumorigenesis of certain secretory breast carcinomas. Because this type of tumors is quite rare, the investigators noted, there have been very few genome-sequencing studies performed in this patient population. Consequently, these researchers aimed to characterize the genomics of secretory breast carcinoma in a study published in Diagnostic Pathology.

“Our study demonstrates the genomic characteristics of a group of secretory breast carcinomas with differences in immunophenotype and biological behavior,” concluded the study authors. “In addition to ETV6::NTRK3 gene fusion, TERT promoter region mutation may be another factor driving tumor progression. This provides insight into the genomic background and clinical treatment of secretory breast carcinomas.”

The investigators focused on seven lesions from five patients diagnosed with secretory breast carcinoma at the Third Affiliated Hospital of Soochow University from 2007 to 2021. Next-generation DNA sequencing was carried out on six of seven lesions. Clinicopathologic features, prognosis, and survival data were collected from medical records.

All patients were female, and the median patient age was 39 at first onset. The median tumor size was 2 cm, and tumors were in the left (n = 3) and right (n = 2) mammary glands; one tumor was associated with axillary lymph node metastasis. No lesions demonstrated progesterone receptor expression or HER2 overexpression. A total of three lesions exhibited estrogen receptor expression, and the Ki67 index was low.

Pan-tyrosine kinase and S-100 protein were diffusely positively expressed in all cases. According to fluorescence in situ hybridization, all lesions demonstrated a t(12;15) (p13;q25) translocation, which led to ETV6::NTRK3 fusion. Sequencing results support that the ETV6::NTRK3 fusion was the main driver of early tumorigenesis, although invasive behavior was attributed to a TERT promoter mutation.

Disclosure: The study authors reported no conflicts of interest.

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