In our previous study [33] we established that GPER mediates a specific gene signature, therefore, we evaluated whether, in IST-MES1 and A549 cells, IGF-I is able to affect the expression of certain GPER target genes like CTGF and EGR1, which have been involved in fibrotic responses in mesothelioma and lung cancer cells [34-36]. The gene discussed is GPER1; the disease is mesothelioma.