Univariate Kaplan–Meier and log-rank analyses demonstrated that although there was no significant association between the gene expression of any of the two Pfn isoforms and the OS of BC patients (supplementary Fig S1), higher Pfn1 (but not Pfn2) gene expression level (>median expression) was significantly associated with an increased risk of recurrence of BC (HR = 1.35 (1.21–1.5), logrank P = 8E−08) (Fig. 1a, b). The gene discussed is PFN2; the disease is breast cancer.