This research study is looking to see how well male breast cancer responds to preoperative treatment with endocrine therapy and which endocrine therapy regimen is the most effective treatment for male breast cancer.

The drugs used in this study are:

* Tamoxifen
* Anastrozole
* Degarelix
* Abemaciclib

This study is researching an investigational drug called REGN7075 by itself and in combination with cemiplimab with or without chemotherapy. The study is focused on patients with certain solid tumors that are in an advanced stage. The aim of the study is to see how safe and tolerable REGN7075 is by itself and in combination with cemiplimab (with or without chemotherapy), and to find out what is the best dose of REGN7075 to be given to patients with advanced solid tumors when combined with cemiplimab (with or without chemotherapy). Another aim of the study is to see how effective REGN7075 by itself, or in combination with cemiplimab (with or without chemotherapy), is at treating cancer patients.

The study is also looking at:

* Side effects that may be experienced by people taking REGN7075 by itself and in combination with cemiplimab with or without chemotherapy
* How REGN7075 works in the body by itself and in combination with cemiplimab with or without chemotherapy
* How much REGN7075 is present in the blood when given by itself and in combination with cemiplimab with or without chemotherapy
* To see if REGN7075 by itself and in combination with cemiplimab with or without chemotherapy works to treat cancer by controlling the proliferation of tumor cells to shrink the tumor

Persons with secondary arm and/or upper quadrant lymphedema following cancer therapies commonly are prescribed complete decongestive therapy as a course of management of their lymphedema. The investigators will perform a repeated-measures cross-over trial to test the hypothesis that mobilization of protein enriched hardened tissue using graded negative pressure therapy in conjunction with complete decongestive therapy (CDT) is more effective to standard CDT alone for secondary lymphedema management.

The primary goal of this study is to evaluate the effectiveness of elacestrant versus standard endocrine therapy in participants with node-positive, Estrogen Receptor-positive (ER+), Human Epidermal Growth Factor-2 negative (HER2-) early breast cancer with high risk of recurrence.

This ComboMATCH patient screening trial is the gateway to a coordinated set of clinical trials to study cancer treatment directed by genetic testing. Patients with solid tumors that have spread to nearby tissue or lymph nodes (locally advanced) or have spread to other places in the body (advanced) and have progressed on at least one line of standard systemic therapy or have no standard treatment that has been shown to prolong overall survival may be candidates for these trials. Genetic tests look at the unique genetic material (genes) of patients' tumor cells. Patients with some genetic changes or abnormalities (mutations) may benefit from treatment that targets that particular genetic mutation. ComboMATCH is designed to match patients to a treatment that may work to control their tumor and may help doctors plan better treatment for patients with locally advanced or advanced solid tumors.

The phase III trial compares the effect of pembrolizumab to observation for the treatment of patients with early-stage triple-negative breast cancer who achieved a pathologic complete response after preoperative chemotherapy in combination with pembrolizumab. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. This trial may help researchers determine if observation will result in the same risk of cancer coming back as pembrolizumab after surgery in triple-negative breast cancer patients who achieve pathologic complete response after preoperative chemotherapy with pembrolizumab.

The purpose of this study is to test the safety and effectiveness of the sequence of two investigational drugs (trastuzumab deruxtecan followed by datopotamab deruxtecan, or datopotamab deruxtecan followed by trastuzumab deruxtecan) to learn whether the treatment works in treating HER2-negative (HER2-low or HER2-0) metastatic breast cancer.

The names of the study drugs involved in this study are:

* Datopotamab deruxtecan (a type of antibody drug conjugate)
* Trastuzumab deruxtecan (a type of antibody drug conjugate)

This phase II ADC MATCH screening and multi-sub-study treatment trial is evaluating whether biomarker-directed treatment with one of three antibody-drug conjugates (ADCs) (sacituzumab govitecan, enfortumab vedotin, and trastuzumab deruxtecan) works in treating patients with solid tumor cancers that have high expression of the Trop-2, nectin-4, or HER2 proteins and that may have spread from where they first started (primary site) to nearby tissue, lymph nodes, or distant parts of the body (advanced) or to other places in the body (metastatic). Precision medicine is a form of medicine that uses information about a person's genes, proteins, and environment to prevent, diagnose, or treat disease in a way that is tailored to the patient. ADCs such as sacituzumab govitecan, enfortumab vedotin, and trastuzumab deruxtecan are monoclonal antibodies attached to biologically active drugs and are a form of targeted therapy. Sacituzumab govitecan is a monoclonal antibody, called sacituzumab, linked to a drug called govitecan. Sacituzumab attaches to a protein called Trop-2 on the surface of tumor cells and delivers govitecan to kill them. Enfortumab vedotin is a monoclonal antibody, enfortumab, linked to an anticancer drug called vedotin. It works by helping the immune system to slow or stop the growth of tumor cells. Enfortumab attaches to a protein called nectin-4 on tumor cells in a targeted way and delivers vedotin to kill them. Trastuzumab deruxtecan is composed of a monoclonal antibody, called trastuzumab, linked to a chemotherapy drug, called deruxtecan. Trastuzumab attaches to HER2 positive tumor cells in a targeted way and delivers deruxtecan to kill them. Personalized treatment with sacituzumab govitecan, enfortumab vedotin, or trastuzumab deruxtecan may be an effective treatment option for patients with advanced or metastatic solid tumors that screen positive for high expression of Trop-2, nectin-4, or HER2, respectively.

This clinical trial will assess the safety and early efficacy of Hydroxychloroquine or Avelumab, with or without Palbociclib, in early-stage ER+ breast cancer patients who are found to harbor disseminated tumor cells (DTCs) in the bone marrow after definitive surgery and standard adjuvant therapy.

This research is to evaluate the effectiveness of Talazoparib as a potential treatment for metastatic breast cancer with a BRCA 1 or BRCA 2 mutation.