While SFRP4+ CAF subsets have been reported in several cancer types (Andersen et al., 2024; Ding et al., 2024; Du et al., 2024; Kieffer et al., 2020; Ning et al., 2024), F4 showed limited similarity to published iCAF/myCAF signatures (Figure 1H; Supplementary Figure S1H). The gene discussed is SFRP4; the disease is cancer.