Moreover, some studies have reported that the expression of CYP19A1 in NSCLC has a high positive correlation with ERβ and can activate the E2/ERβ signalling pathway by promoting oestrogen production, leading to the progression of NSCLC; thus, CYP19A1 can be used as a predictor of patient survival [29, 30]. This evidence concerns the gene ESR2 and non-small cell lung carcinoma.