Phase I/IIa Study of 68GaNOTA-Anti-MMR-VHH2 for PET/CT

PART I: Inclusion Criteria: Patients will only be included in the study if they meet all of the following criteria: * Patients who have given informed consent * Patients at least 18 years old * Patients with local, locally advanced or metastatic disease of a malignant solid tumor. In order to minimize partial volume effect the diameter of at least 1 tumor lesion should be ≥ 10 mm in short axis for invaded adenopathies and ≥ 10 mm in long axis for all other types of lesions. Exclusion Criteria: Patients will not be included in the study if one of the following criteria applies: * Eastern Cooperative Oncology Group (ECOG) performance status 3 or higher * Pregnant patients * Breast feeding patients * Patients with abnormal liver (Bilirubin ≥1.5 x ULN, ALT (SGPT) ≥3 x ULN) or kidney function (Serum creatinine clearance ≤50 ml/min as calculated with Cockcroft-Gault formula) * Patients with recent (\< 1 week) gastrointestinal disorders (CTCAE v4.0 grade 3 or 4) with diarrhea as major symptom * Patients with any serious active infection * Patients who have any other life-threatening illness or organ system dysfunction, which in the opinion of the investigator would either compromise patient safety or interfere with the evaluation of the safety of the test radiopharmaceutical * Patients who cannot communicate reliably with the investigator * Patients who are unlikely to cooperate with the requirements of the study * Patients who are unwilling and/or unable to give informed consent * Patients at increased risk of death from a pre-existing concurrent illness * Patients who participated already in this study PART II: Inclusion Criteria: Patients will only be included in the study if they meet all of the following criteria: * Patients who have given informed consent * Patients at least 18 years old * Patients diagnosed with a local, locally advanced or metastatic disease, with any of the following cancer types : * Triple-negative breast carcinoma, * Hormone-receptor negative (HR-), HER2+ breast carcinoma, with HER2-expression defined as HER2+ on ISH or 3+ on IHC, as determined by local assessment on any of the available cancer tissues * Melanoma * Patients who have had a biopsy of at least one lesion or who are planned to undergo standard-of-care resection or biopsy of at least one lesion, in order to minimize partial volume effect, the diameter of that lesion should be ≥ 10 mm in short axis for invaded adenopathies and ≥ 10 mm in long axis for all other types of lesions. Exclusion Criteria: Patients will not be included in the study if one of the following criteria applies: * Eastern Cooperative Oncology Group (ECOG) performance status 3 or higher * Pregnant patients * Breast feeding patients * Patients with recent (\< 1 week) gastrointestinal disorders (CTCAE v4.0 grade 3 or 4) with diarrhea as major symptom * Patients with any serious active infection * Patients who have any other life-threatening illness or organ system dysfunction, which in the opinion of the investigator would either compromise patient safety or interfere with the evaluation of the safety of the test radiopharmaceutical * Patients who cannot communicate reliably with the investigator * Patients who are unlikely to cooperate with the requirements of the study * Patients who are unwilling and/or unable to give informed consent * Patients at increased risk of death from a pre-existing concurrent illness * Patients who participated already in this study