Patient description: The patient is a 41-year-old man and a known case of Acromegaly who underwent transsphenoidal surgery 4 months ago. He came to the clinic for the follow up lab studies after his primary resection surgery. His lab study shows the IGF-1 level of 4.5 ULN adjusted by sex and age. His random GH level is 4 ug/L. The recent brain MRI confirmed the residual pituitary tumor. His past medical history is only significant for acromegaly due to pituitary adenoma and the recent surgery. After his surgery he takes only vitamin D and multivitamins.

Clinical trial eligibility criteria: eligible ages (years): 1.0-21.0,  Advanced Malignant Solid Neoplasm Recurrent Childhood Ependymoma Recurrent Ewing Sarcoma Recurrent Glioma Recurrent Hepatoblastoma Recurrent Kidney Wilms Tumor Recurrent Langerhans Cell Histiocytosis Recurrent Malignant Germ Cell Tumor Recurrent Malignant Glioma Recurrent Medulloblastoma Recurrent Neuroblastoma Recurrent Non-Hodgkin Lymphoma Recurrent Osteosarcoma Recurrent Peripheral Primitive Neuroectodermal Tumor Recurrent Rhabdoid Tumor Recurrent Rhabdomyosarcoma Recurrent Soft Tissue Sarcoma Refractory Ependymoma Refractory Ewing Sarcoma Refractory Glioma Refractory Hepatoblastoma Refractory Langerhans Cell Histiocytosis Refractory Malignant Germ Cell Tumor Refractory Malignant Glioma Refractory Medulloblastoma Refractory Neuroblastoma Refractory Non-Hodgkin Lymphoma Refractory Osteosarcoma Refractory Peripheral Primitive Neuroectodermal Tumor Refractory Rhabdoid Tumor Refractory Rhabdomyosarcoma Refractory Soft Tissue Sarcoma Patient must have enrolled onto APEC1621SC and must have been given a treatment assignment to MATCH to APEC1621I based on the presence of an actionable mutation In addition to the actionable mutations, positive Rb expression by immunohistochemistry is required for study enrollment Patients must have a body surface area >= 0.87 m^2 at enrollment Patients must have radiographically measurable disease at the time of study enrollment; patients with neuroblastoma who do not have measurable disease but have MIBG+ evaluable disease are eligible; measurable disease in patients with CNS involvement is defined as tumor that is measurable in two perpendicular diameters on magnetic resonance imaging (MRI) and visible on more than one slice Note: The following do not qualify as measurable disease Malignant fluid collections (e.g., ascites, pleural effusions) Bone marrow infiltration except that detected by MIBG scan for neuroblastoma Lesions only detected by nuclear medicine studies (e.g., bone, gallium or positron emission tomography [PET] scans) except as noted for neuroblastoma Elevated tumor markers in plasma or cerebrospinal fluid (CSF) Previously radiated lesions that have not demonstrated clear progression post radiation  Pregnant or breast-feeding women will not be entered on this study due to risks of fetal and teratogenic adverse events as seen in animal/human studies; pregnancy tests must be obtained in girls who are post-menarchal; males or females of reproductive potential may not participate unless they have agreed to use an effective contraceptive method for the duration of study treatment; females study participants of child-bearing potential and their partners, should agree to use highly effective forms of contraception for at least 3 weeks after the last dose of palbociclib; male study participants should avoid fathering a child, donating sperm, and should agree to use highly effective forms of contraception for at least 3 months after the last dose of palbociclib Concomitant medications Corticosteroids: Patients receiving corticosteroids who have not been on a stable or decreasing dose of corticosteroid for at least 7 days prior to enrollment are not eligible; if used to modify immune adverse events related to prior therapy, >= 14 days must have elapsed since last dose of corticosteroid Investigational drugs: Patients who are currently receiving another investigational drug are not eligible Anti-cancer agents: Patients who are currently receiving other anti-cancer agents are not eligible Anti-GVHD agents post-transplant: Patients who are receiving cyclosporine, tacrolimus or other agents to prevent graft-versus-host disease post bone marrow transplant are not eligible for this trial CYP3A4 agents: Patients who are currently receiving drugs that are strong inducers or inhibitors of CYP3A4 are not eligible; strong inducers or inhibitors of CYP3A4 should be avoided from 14 days prior to enrollment to the end of the study; Note: CYP3A4 inducing anti-epileptic drugs and dexamethasone for CNS tumors or metastases, on a stable dose, are allowed Patients who have an uncontrolled infection are not eligible Patients who have received a prior solid organ transplantation are not eligible Patients who in the opinion of the investigator may not be able to comply with the safety monitoring requirements of the study are not eligible