It was found that oe-MUC1 promoted MUC1 expression in ESCC cells but did not affect SIGLEC9 expression in the co-cultured TAMs, and artificial inhibition of SIGLEC9 in TAMs did not affect the MUC1 expression in the co-cultured ESCC cells as well (Fig. 7c, d). Here, MUC1 is linked to esophageal squamous cell carcinoma.