[{"from": "human", "value": "Provide a description of this molecule. [C][N][C@@H1][Branch2][=Branch1][#Branch2][C][=Branch1][C][=O][N][C@H1][Branch2][Branch1][Branch2][C][=Branch1][C][=O][N][C@H1][Branch2][Ring1][S][C][=Branch1][C][=O][N][C][C][=Branch1][C][=O][N][C@@H1][Branch1][=Branch1][C][Ring2][Ring1][Ring1][=O][C][C][=C][C][=C][Branch1][Branch1][C][=C][Ring1][=Branch1][O][C][C][=C][C][=C][C][=C][C][=C][Ring1][=Branch1][C][=C][Ring1][#Branch2][C][C][C][N][=C][Branch1][C][N][N][C][C][C][N][C][=Branch1][C][=O][C][=C][C][=C][Branch1][Branch1][C][=C][Ring1][=Branch1][C][N][C][=Branch1][C][=O][C][N][C][C][N][Branch2][Ring1][O][C][C][N][Branch1][S][C][C][N][Branch1][Branch1][C][C][Ring1][N][C][C][=Branch1][C][=O][O-1][C][C][=Branch1][C][=O][O-1][C][C][=Branch1][C][=O][O-1].[68Ga+3]"}, {"from": "gpt", "value": "The molecule is a radioconjugate composed of a synthetic, cyclic pentapeptide analog of stromal-cell derived factor-1 (SDF-1 or CXCL12), which is a ligand for chemokine receptor C-X-C chemokine receptor type 4 (CXCR4), that is radiolabeled, via the macrocyclic chelating agent dodecanetetraacetic acid (DOTA), with the radioisotope gallium Ga 68 (Ga68; 68Ga), with potential use for imaging CXCR4-expressing cells upon positron emission tomography (PET)/computed tomography (CT). Upon administration of 68Ga pentixafor, the pentixafor moiety targets and binds to CXCR4-expressing cancer cells. Upon PET/CT, CXCR4-expressing cancer cells can be visualized and the expression status of the receptor can be assessed. CXCR4, a marker of poorly differentiated cells, is overexpressed on various cancer cells, and plays a key role in tumor growth, progression, invasiveness and metastasis."}]