ERBB2 and breast cancer: HR + HER2- BC had the fewest fusions (median: 7, IQR: 3–15) compared to TNBC (median: 9, IQR: 4.75–14), HR-HER2 + BC (median: 9.5, IQR: 5.75–18.25), and HR + HER2 + BC (median: 10, IQR: 6–13) (p = 0.16).