Based on the relative expression levels of C9orf142 in these cell lines and their tumourigenic and metastatic properties, we stably overexpressed Flag‐C9orf142 in cells with low expression of C9orf142 (Figure 2B), whereas knocked down endogenous C9orf142 in cells with high expression of C9orf142 by lentiviral infection, respectively (Figure 2C). This evidence concerns the gene PAXX and infection.