TET2 Mutations in Myelodysplastic Syndromes and Acute Myeloid Leukemia With Azacitidine + Ascorbic Acid

Inclusion Criteria: * Patients must have a confirmed heterozygous TET2 mutations identified by next generation targeted deep sequencing. * Patients must have MDS, or MDS/MPN overlap defined by 2016 World Health Organization (WHO) criteria. Both newly diagnosed or previously treated MDS or MDS/MPN patients are eligible as long as the patient has never received prior treatment with azacitidine or decitabine. * Patients with Leukemic/blast phase transformation MPN. * Patient with AML according to 2016 WHO criteria. * Newly diagnosed patients who are ineligible or declined to receive intensive chemotherapy after discussion of risks and benefits of that approach or patients with primary refractory/relapsed AML. * Patients with active central nervous system (CNS) leukemia eligible at the discretion of treating physician. * Relapse/Refractory is defined as at least 1 course of treatment for AML excluding any patients treated with azacitidine or decitabine. * Patients should be off any prior treatment or line of therapy for 2 weeks prior to start study with the exception of hydrea (Hydroxyurea). * Prior therapy with hydroxyurea, biological or targeted therapy (e.g. flt3 inhibitors, other kinase inhibitors) or hematopoietic growth factors is allowed. * Eastern Cooperative Oncology Group (ECOG) performance status ≤ 3. * Patients must have normal organ and marrow function as defined at the discretion of the treating physician and PI. * Women of childbearing potential must have a negative serum or urine pregnancy test within 10-14 days prior to enrollment. * Patients must have the ability to understand and the willingness to sign a written informed consent document. * Patient must be willing to comply with all aspects of the protocol including completing the drug diary. * Patient must discontinue any and all use of multivitamin and/or vitamin c medication 24 hours before first dose of Ascorbic Acid. Exclusion Criteria: * Any prior treatment with azacitidine or decitabine. * Patients diagnosed with acute promyelocytic leukemia (APL), AML-M3. * Patients receiving other active treatment for their myeloid malignancy including investigational agents with the exception of hydrea for white blood cell control. * Nursing or pregnant women. * History of allergic reactions to either azacitidine or ascorbic acid. * Patients with uncontrolled intercurrent illness including, but not limited to ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements. * Patients with higher risk of bleeding (deemed by the treating physician) or on anticoagulation. * Patients who are unwilling or unable to comply with all study requirements.