A vector in which the suicide gene uracil phosphoribosyltransferase (UPRT), internal ribosome entry site (IRES), and EGFP gene were ligated downstream of the PSTC‐1–114 was constructed (Figure 3A left and Figure S1A) and transfected into STC‐1‐expressing lung cancer cell lines PC‐9, A549, and H1299. Here, UPRT is linked to lung cancer.