PTCH1 and skin basal cell carcinoma: However, it is important to note that whilst UVB was able to upregulate endogenous FOXM1B and that FOXM1 has been shown to induce its own expression [30], other factors such as mutations in PTCH and SMO with subsequent upregulation of Gli transcription factors are most likely to be responsible for the initial upregulation of FOXM1 in BCC ([8]).