Thereafter, immunohistochemistry was carried out to detect the protein levels of SPARCL1, FAK, p-FAK, Akt, and p-Akt in tumors; the result indicated that the protein expression of SPARCL1 in tumors injected with the serum EVs of ESCC patients was downregulated, whereas those of p-FAK and p-Akt were upregulated (Figure 8E). Here, SPARCL1 is linked to esophageal squamous cell carcinoma.