To screen out the shRNA with the best knockout effect of the target gene, we infected the SNU‐5 cell line (Cell line with highest KIRREL protein expression) with lentiviruses of SH‐NC, SH‐1, SH‐2 and SH‐3 and recorded the lentivirus infection by fluorescence microscopy (Figure 4A). Here, KIRREL1 is linked to infection.