ERBB2 and breast cancer: In patients with HER2 overexpressing breast cancer that received trastuzumab, there was no significant difference in 5 year disease-free survival (DFS) between those with positive and negative PRPF38B membranous expression [HR (95% CI) = 1.75 (1.7–2.5); p = 0.49] (Figure 4A(ii)).