(A) Real-time PCR analysis was performed to examine the expression of GREM1 in a variety of skin tumors, including basal cell carcinomas (BCCs, n = 18), squamous cell carcinomas (SCCs, n = 9), melanomas (MNs, n = 8), pilomatricomas (PMCs, n = 8), trichoepitheliomas (TEs, n = 7), eccrine poromas (EPs, n = 9), hidradenomas (HADs, n = 9), and spiradenomas (SPAs, n = 7). *P < 0.05; **P < 0.00; 5***P < 0.001; ns, not significant. (B) The proportion of RNA in situ hybridization (ISH) scores for GREM1 in skin tumors. Analysis of GREM1 expression by RNA ISH was performed on tissue microarrays, including BCCs (n = 81), SCCs (n = 17), MNs (n = 5), PMCs (n = 10), TEs (n = 16), EPs (n = 11), HDAs (n = 9), and SPAs (n = 10). RNA ISH for GREM1 was scored from 0 to 4, reflecting the intensity of GREM1 expression.