CXCL12 and lung cancer: Moreover, adding CXCL12‐shRNA into THP‐1 cells within the coculture system can also lead to reversing the infiltrated macrophages‐increased ERα expression in A549 and H1299 lung cancer cells (Fig. 7B) (see the altered CXCL12 expression in THP‐1 cells via western blot analysis in the Fig. S4D).