For instance, while SMA and IL-6 expression can distinguish between myCAFs and iCAFs as discussed previously, these markers may also not resolve other heterogeneous and transcriptionally distinct CAF subpopulations (31) such as apCAFs or vCAFs which express high levels of IL-6 and activate STAT3 in tumor cells as observed in cholangiocarcinoma (34). Here, IL6 is linked to cholangiocarcinoma.