We employed Transwell coculture experiments and found that SIRPγ overexpression in A549 and H1975 cells (representing SIRPγhi cells) in comparison with vector expression in cancer cells (representing SIRPγlo/– cells) in the upper chamber showed increased CD47 expression in vector-expressing A549 and H1975 cells (representing SIRPγlo/– cells) from the lower chamber in a time-dependent manner (Figure 5I and Supplemental Figure 5F), suggesting that the SIRPγhi cancer cell population transmits a paracrine signal to induce protein CD47 expression in the SIRPγlo/– cancer cell population. Here, CD47 is linked to cancer.