ERVW-1 and ductal breast carcinoma in situ: A potential disconnect between Gag and Env targeting antibodies may also explain the comparable positivity for HERV‐K (HML‐2) Env antibodies in early and late stage melanoma reported in other studies26 Antibodies to HERV‐K (HML‐2) Env SU, Rec, and Np9 have also been detected in ductal carcinoma in situ, the earliest stage of breast cancer, and were increased in later stage invasive ductal carcinoma.33