ERBB2 and breast cancer: Though we could not exclude the possibility of having an inaccurate observation due to the small sample cohort (i.e., 219 ER-HER2+ cases in Fig. 2), the higher RFS, in general, for HER2+ patients (both ER-HER2+, ER+HER2+) together with the significantly poor RFS for HER2- patients harboring SNRPD1 over-expression suggested the prominent role of HER2 in stratifying breast cancers towards the sensitivity of tumors to SNRPD1 status.