JCO Precision Oncology | 2021
STRN-ALK Fusion–Positive Case of Breast Cancer With Response to Alectinib
Abstract
Anaplastic lymphoma kinase (ALK) fusion rearrangements were first described in anaplastic large cell lymphoma and subsequently defined in non–smallcell lung cancer (NSCLC) as capable of inducing malignant transformation. Such fusion events in cancer involve numerous partner genes, but invariably retain the ALK kinase domain coded for by exon 20 and are present in about seven percent of NSCLC cases. Recent data have demonstrated high overall response rates and improved progression-free survival with ALK-directed kinase inhibitors including entrectinib, alectinib, and brigatinib in NSCLC, but have limited data in other tumor types. One recent study of 4,854 genomically sequenced breast cancer (BC) cases identified one EML4-ALK fusion in a patient with estrogen receptor–positive disease. Another study using exon arrays identified another five caseswith EML4ALK; however, we are not aware of other published cases involving EML4 or other ALK fusion partners. Here, we report the first case of STRN-ALK fusion– positive BC in a patient who responded to alectinib.