As shown in Figure 1A, Ab27 bound to HCT-116, HT-29 (colon), SNU-398 (liver), SNU-638 (stomach), and C8161 (melanoma) cancer cells expressing endogenous TM4SF5, and suppression of TM4SF5 expression by siRNA decreased Ab27 binding to these cells, confirming the specificity of Ab27. Here, TM4SF5 is linked to melanoma.