ACTA1 and cancer: Taken together with our previous finding that PSCs cultured with conditioned media from cancer cells induces a transition from POSTN‐high to POSTN‐low subtypes [10], these data suggested that POSTN‐positive/αSMA‐low CAFs may be the initial reactive CAFs emerging at early steps of PDAC carcinogenesis from the peri‐acinar PSCs.