As described above (Section 2.1.1), POSTN was expressed in CAFs in various skin cancers (cSCC, BCC, EMPD, DFSP, Merkel cell carcinoma, and mycosis fungoides) [35,36,37,38,39,40], contributing to the development of the tumor microenvironment in each cancer. The gene discussed is POSTN; the disease is Merkel cell skin cancer.