this study evaluates the cellular and humoral immune response to seasonal influenze vaccination in PTEN Hamartoma Tumor Syndrome. All subjects will be administered flu vaccination, half of the subjects will be control subjects.

Inclusion Criteria:

• Must be diagnosed with PHTS based on genetic testing
• Must be a Radboudumc patient
• Must be 18 years or older
• Must be mentally competent
• Must have provided written informed consent to participate in the study
• Must be able to adhere to visit schedule and available to complete the study

Exclusion Criteria:

• • Known history of significant medical disorder, which in the investigator's judgment might confound the results of the study or pose additional risk to the subject by participation in the study

  • Known hypersensitivity to previous influenza vaccinations (Anaphylaxis)
  • Must not be allergic to chicken eggwhite
  • Pregnancy at start of study
  • Immunocompromised patients and those receiving concomitant immunosuppressive therapy or other immune modulating drugs including chronic steroid treatment.
  • Bleeding disorders including haemophilia and thrombocytopenia or treatment with anticoagulants(Due to risk of intramuscular hematoma after injection)
  • Must not have received vaccination with attenuated pathogens in the 4 weeks leading up to study. (Measles, mumps, rubella, yellow fever, rotavirus, BCG, typhoid)