FN1 and cancer: Interestingly, we found that communication between fibrocytes and cancer cells altered not only the cancer cell phenotype but also the fibrocyte phenotype toward a more mature connective tissue phenotype with further increased mRNA expression of collagen 1A1 (COL1A1) and 3A1 (COL3A1) and fibronectin (FN1) (Fig. 6D and Figs. S6C–S6F).