IHC staining for Tspan5 protein expressed in our cohort with 139 HCC clinical samples showed that Tspan5 expression was mainly located on cell membranes and in cytoplasm (Fig. S1A) and was significantly associated with invasive depth (P = 0.032) and TNM stage (P = 0.015) but not with gender, age, tumour size or pathological grade. Here, TSPAN5 is linked to hepatocellular carcinoma.