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Recombinant human erythropoietin (rhuEpo) is used clinically to treat anaemia. However, rhuEpo-treated cancer patients show decreased survival rates and erythropoietin receptor (EpoR) expression has been found in patient tumour tissue. Thus, rhuEpo application might promote EpoR(+) tumour progression. We therefore developed the positron emission tomography (PET)-probe (68)Ga-DOTA-rhuEpo and evaluated its performance in EpoR(+) A549 non-small-cell lung cancer (NSCLC) xenografts.(68)Ga-DOTA-rhuEpo was generated by coupling DOTA-hydrazide to carbohydrate side-chains of rhuEpo. Biodistribution was determined in tumour-bearing mice 0.5, 3, 6, and 9 h after probe injection. Competition experiments were performed by co-injecting (68)Ga-DOTA-rhuEpo and rhuEpo in five-fold excess. Probe specificity was further evaluated histologically using Epo-Cy5.5 stainings.The blood half-life of (68)Ga-DOTA-rhuEpo was 2.6 h and the unbound fraction was cleared by the liver and kidney. After 6 h, the highest tumour to muscle ratio was reached. The highest (68)Ga-DOTA-rhuEpo accumulation was found in liver (10.06 ± 6.26%ID/ml), followed by bone marrow (1.87 ± 0.53%ID/ml), kidney (1.58 ± 0.39%ID/ml), and tumour (0.99 ± 0.16%ID/ml). EpoR presence in these organs was histologically confirmed. Competition experiments showed significantly (p 0.05) lower PET-signals in tumour and bone marrow at 3 and 6 h.(68)Ga-DOTA-rhuEpo shows favourable pharmacokinetic properties and detects EpoR specifically. Therefore, it might become a valuable radiotracer to monitor EpoR status in tumours and support decision-making in anaemia therapy.• PET-probe (68) Ga-DOTA-rhuEpo was administered to assess the EpoR status in vivo • (68) Ga-DOTA-rhuEpo binds specifically to EpoR positive organs in vivo • Tumour EpoR status determination might enable decision-making in anaemia therapy with rhuEpo.

The palladacycle [Pd(μ-O2CMe){κ2C,N-4-MeC6H3N(Me)NO}]2 readily undergoes bridge cleavage reactions with a variety of compounds containing donor functionalities including thioamides, 8-hydroxyquinoline, thioureas, selenoureas, acetylacetone derivatives, dithiocarbamates, xanthates, as well as bidentate N-donors to afford either the monomeric, neutral Pd(II) complexes [Pd{κ2C,N-4-MeC6H3N(Me)NO}{L-L}] or the monocationic complexes [Pd{κ2C,N-4-MeC6H3N(Me)NO}(N-N)]PF6 in high yields. A series of 15 different complexes was prepared and fully characterised spectroscopically and, in some cases, by X-ray diffraction. It was also found that the dithiocarbamato complex undergoes a disproportionation reaction in solution to give the bis(cyclometallated) complex [Pd{κ2C,N-4-MeC6H3N(Me)NO}2] as well as the bis(dithiocarbamato) complex [Pd{κ2S-S2CNEt2}2].