NCI Dictionary of Cancer TermsThe NCI Dictionary of Cancer Terms features 8,572 terms related to cancer and medicine. We offer a widget that you can add to your website to let users look up cancer-related terms. Get NCI’s Dictionary of Cancer Terms Widget.- listen (veh-lih-PAR-ib)- A substance being studied in the treatment of breast cancers caused by mutations (changes) in the BRCA1 and BRCA2 genes. It is also being studied in the treatment of other types of cancer. It blocks an enzyme involved in many functions of the cell, including the repair of DNA damage. DNA damage may be caused by normal cell actions, UV light, some anticancer drugs, and radiation used to treat cancer. Veliparib may cause cancer cells to die. It is a type of poly(ADP-ribose) polymerase inhibitor. Also called ABT-888 and PARP-1 inhibitor ABT-888.