Posted: Thursday, May 5, 2022
NTRK fusions in breast cancer are rare, with a prevalence rate of less than 1%, according to a recent study. However, amplifications of NTRK1 seem to be more common and have been associated with basal cancers and TP53 mutations. Athina Stravodimou, MD, of CHUV, Lausanne, Switzerland, and Ioannis A. Voutsadakis, MD, PhD, of Sault Area Hospital, Ontario, Canada, reported that NTRK molecular lesions other than fusions were observed more often than fusions. These study findings were published in the World Journal of Clinical Oncology.
“In breast cancer, fusions involving the neurotrophic receptor tyrosine kinase receptors are rarely seen and concern exclusively the secretory subtype. In non-secretory breast carcinomas, amplifications are observed in a minority of cases,” said the authors.
The study searched available genomic breast cancer data sets in the cBioportal platform for identification and characterization of known cases of breast cancer with fusions and other molecular abnormalities involving NTRK1, NTRK2, and NTRK3. (cBioportal is a multidimensional platform for molecular studies and clinical data.) In the cBioportal, the study focused on information in the project GENIE study and The Cancer Genome Atlas (TCGA).
In the Project GENIE data set, 11,886 patients had breast cancer, and 27 patients (0.22%) had fusions in one of the three NTRK genes. Of the 27 patients, 2 were male. A total of 32 fusions involving the three NTRK genes were present in the 27 patients (5 patients had more than one different fusion). The most frequent fusions involved NTRK3 in 16 samples, followed by NTRK1 in 13 samples, and NTRK2 in 3 samples. These cases are not identified as secretory in the database, suggesting the histologic characterization may not always be evident. In the TCGA data set, fusions involving the three NTRK genes were not observed. The most common molecular lesions were amplifications observed in 9.8% of patients, most commonly in NTRK1 (7.9%) and more rarely in NTRK3 (1.9%) and in NTRK2 (0.2%).
Disclosure: The study authors reported no conflicts of interest.