Methods and compositions related to antibody fragments that bind to tumor-associated glycoprotein 72 (TAG-72)

1. An antibody fragment which specifically binds tumor-associated glycoprotein 72 (TAG-72), wherein the antibody fragment comprises SEQ ID NO: 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, or 45.

2. The antibody fragment of claim 1 , wherein the fragment has increased tissue penetrance compared to full-length antibodies (IgG) and fragment antigen binding (Fab) domains.

3. The antibody fragment of claim 1 , wherein the antibody fragment comprises a heavy chain variable region comprising SEQ ID NO: 10, and a light chain variable region comprising SEQ ID NO: 11.

4. The antibody fragment of claim 1 , wherein said antibody fragment has an antigen binding affinity for sialyl-Tn which is at least 25% that of 3E8.

5. The antibody fragment of claim 1 , wherein the antibody fragment is a diabody, a triabody, a tetrabody, or a combination of any of those.

6. A composition comprising the antibody fragment of claim 1 and a pharmaceutically acceptable carrier.

7. The composition of claim 6 , wherein said antibody fragment is, directly or indirectly, associated with or linked to an effector moiety having therapeutic activity, and the composition is suitable for the treatment of cancer.

8. The composition of claim 7 , wherein said effector moiety is a radionuclide, therapeutic enzyme, anti-cancer drug, cytokine, cytotoxin, or anti-proliferative agent.

9. The composition of claim 6 , wherein said antibody fragment is, directly or indirectly, associated with or linked to a detectable label, and the composition is suitable for detection of cancer.

10. The composition of claim 9 , wherein the detectable label is a radionuclide or an enzyme.