Phase II ABT-888 With Cyclophosphamide

Background: \- The experimental cancer treatment drug ABT-888 (Veliparib) works by preventing deoxyribonucleic acid (DNA) repair in tumor cells. Cyclophosphamide is a cancer treatment drug that works by causing DNA damage in cells, including cancer cells, resulting in cell death. However, because cyclophosphamide has strong and unpleasant side effects, researchers are interested in finding drugs that can be given in combination with cyclophosphamide that will allow a lower dose of cyclophosphamide to be given with similar effects. The combination of ABT-88 and cyclophosphamide may be an effective treatment for some types of cancer, such as certain kinds of breast or ovarian cancer and non-Hodgkin's lymphoma that often do not respond to standard therapies. Objectives: \- To evaluate the safety and effectiveness of ABT-888 and cyclophosphamide in ovarian and breast cancer and in non-Hodgkin's lymphoma that have not responded to standard treatments. Eligibility: \- Individuals at least 18 years of age who have been diagnosed with (1) (Breast cancer 1/2) BRCA1/2 ovarian cancer, primary peritoneal or ovarian high-grade carcinoma, or fallopian tube cancer; (2) triple-negative breast cancer (not responsive to hormone-related therapy); or (3) low grade non-Hodgkin's lymphoma. Design: * Participants will be screened with a full medical history and physical examination, blood and urine tests, and tumor imaging studies. Participants will be divided into two groups with different treatment subgroups. * Group 1: Participants who have BRCA-positive ovarian cancer, primary peritoneal or ovarian high-grade serous carcinoma, or fallopian tube cancer * Participants will receive either the combination of ABT-888 and cyclophosphamide, or cyclophosphamide alone. * Participants will take the study drug by mouth once a day for 21-day cycles of treatment, and will keep a diary to record drug doses and any side effects. * Participants will have clinic visits with blood and urine test