Immunohistochemical (IHC) staining for CAF markers FAP and PDGFRβ showed prominent expression in the tumor stroma of most samples, particularly CAF#1 and CAF#7, with variable intensity in others (e.g., CAF#3 showing lower FAP/PDGFRβ), confirming the presence and heterogeneity of CAF populations within the primary tumors (Fig. 1B, middle and bottom rows, Supplementary Fig. 1). Here, FAP is linked to neoplasm.