Intratumoral stromal cells derived from lung cancer tissues did not express aromatase; however, they produced oncostatin M and interleukin (IL)-6, which induced aromatase gene expression in lung adenocarcinoma cell lines (Figure 2) [66], indicating the importance of intratumoral estrogen production induced by CAFs in NSCLC tissues as well as estrogen produced by the ovaries. This evidence concerns the gene CYP19A1 and non-small cell lung carcinoma.