A study by Pyka et al. revealed that quantitative (SUV) analysis of 68Ga-PSMA ligand PET was not able to discriminate reliably between pulmonary metastases and primary lung cancer in PC patients as primary lung cancer lesions can also show high PSMA-expression by 68Ga-PSMA ligand PET. The gene discussed is FOLH1; the disease is pachyonychia congenita.