We compared 22 patients with distant metastases (M1) and 22 patients without distant metastases (M0) in PDAC (Figure 5A), and 24 patients with distant metastases (M1) and 23 patients without distant metastases (M0) in HCC (Figure 5B), and we found that the patients who developed metastatic disease had higher levels of serum K102-Env proteins. Here, ERVW-1 is linked to metastatic neoplasm.