Patient description: The patient is a 37-year-old woman who came to the clinic for a routine Pap smear. The test revealed stage 1B of cervical cancer. The patient tested positive for HPV 16. She has three sexual partners and four children. She underwent tubal ligation. She smokes 30 packs/year and drinks alcohol frequently. She is otherwise healthy. She was offered a radical hysterectomy.

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Metastatic Breast Cancer Invasive Breast Cancer Somatic Mutation Breast Cancer (BRCA1) Somatic Mutation Breast Cancer (BRCA2) CHEK2 Gene Mutation ATM Gene Mutation PALB2 Gene Mutation RAD51 Gene Mutation BRIP1 Gene Mutation NBN Gene Mutation Patients must have histologically confirmed invasive breast cancer with stage IV disease, either biopsy proven or with unequivocal evidence of metastatic disease by physical examination or radiological study Cohorts 1 and 2: Documented germline (Cohort 1) or somatic mutation or homozygous deletion (Cohort 2) in one of the DNA repair genes listed below that is deleterious or suspected to be deleterious, and no germline BRCA1 or BRCA2 mutation. The mutation may be identified through any CLIA approved NGS panel ATM, ATR, BARD1, BRIP1 (FANCJ), CHEK2 , FANCA, FANCC, FANCD2, FANCE, FANCF, FANCM, MRE11A, NBN, PALB2, RAD50, RAD51C, RAD51D, plus other HR-related genes at the discretion of Dr. Tung with the key study collaborators (see details below in italics). (Cohorts 1 or 2) -- Documented somatic mutation (deleterious or suspected deleterious) in BRCA1 or BRCA2 through any CLIA approved lab only if in addition to the lack of a germline BRCA1/2 mutation is demonstrated through a CLIA approved lab. Patients with germline mutations in BRCA1/2 are NOT eligible for this study. (Cohort 2 only) Cohort 1a: germline PALB2 mutation - The mutation must be identified through a CLIA-approved NGS panel. Mutations must be reviewed and confirmed by Dr. Tung to meet prior to registration Cohort 2a: somatic mutation of BRCA 1 or BRCA 2 - The mutation must be identified through a CLIA-approved NGS panel. Mutations must be reviewed and confirmed by Dr. Tung to meet prior to registration. Documentation of absence of germline mutation in BRCA 1/2 is required All deep (homozygous) deletions, frameshift mutations and truncating mutations in the genes listed above are eligible as well as missense variants in these genes that have previously been reported as pathogenic or likely pathogenic. If there is a discrepancy between two labs regarding the pathogenicity of a particular variant, the final decision regarding will be determined by the study steering committee At least one measurable lesion that can be accurately assessed at baseline by CT (MRI where CT is contraindicated) and is suitable for repeated assessment as per 1.1. -  Any previous treatment with a PARP inhibitor, including olaparib Germline BRCA1 or BRCA2 mutation Patients with myelodysplastic syndrome/acute myeloid leukemia or with features suggestive of MDS/AML Patients with symptomatic uncontrolled brain metastases. A scan to confirm the absence of brain metastases is not required. Patients with spinal cord compression unless considered to have received definitive treatment for this and evidence of clinically stable disease for 28 days Major surgery within 2 weeks of starting study treatment and patients must have recovered from any effects of any major surgery Concomitant use of known strong CYP3A inhibitors (e.g., itraconazole, telithromycin, clarithromycin, protease inhibitors boosted with ritonavir or cobicistat, indinavir, saquinavir, nelfinavir, boceprevir, telaprevir) and grapefruit, grapefruit juice or any product containing grapefruit,or moderate CYP3A inhibitors (e.g., ciprofloxacin, erythromycin, diltiazem, fluconazole, verapamil). The required washout period prior to starting olaparib is 2 weeks Concomitant use of known strong (e.g., phenobarbital, enzalutamide, phenytoin, rifampicin, rifabutin, rifapentine, carbamazepine, nevirapine and St John's Wort) or moderate CYP3A inducers (e.g., bosentan, efavirenz, modafinil). The required washout period prior to starting olaparib is 5 weeks for enzalutamide or phenobarbital and 3 weeks for other agents Patients considered a poor medical risk due to a serious, uncontrolled medical disorder, non-malignant systemic disease or active, uncontrolled infection. Examples but are not limited to, uncontrolled ventricular arrhythmia, recent (within 3 months) myocardial infarction, uncontrolled major seizure disorder, unstable spinal cord compression, superior vena cava syndrome, extensive interstitial bilateral lung disease on High Resolution Computed Tomography (HRCT) scan or any psychiatric disorder that prohibits obtaining informed consent Persistent toxicities (≥CTCAE grade 2) caused by previous cancer therapy, excluding alopecia Immunocompromised patients, e.g., patients who are known to be serologically positive for human immunodeficiency virus (HIV)