For example, αSMA+ CAFs (see Abbreviations, Box 2) are dominantly found in pancreatic carcinoma and might reflect the activation of resident stellate cells (Ferdek and Jakubowska, 2017; Ozdemir et al., 2014), whereas PDGFRα+ CAFs (Box 2) in melanoma might reflect the activation and expansion of resident dermal fibroblasts that express this marker (Anderberg et al., 2009; Lynch and Watt, 2018). This evidence concerns the gene ACTA1 and exocrine pancreatic carcinoma.