A previous study using markers for CAF in breast cancer (48)defined CAF-S1 as well as CAF-S4 in human NB (49), and to further investigate FNB-CAF, we mechanistically classified fibroblasts in F1 (Figure 1D) and obtained a total of four subpopulations, namely Fib-1, Fib-2, Fib-3 and Fib- 4 (Figure 6A). This evidence concerns the gene FBL and breast cancer.