Described are diagnostic and pharmaceutical compositions containing amicroorganism or cell for in vivo detection, imaging and/or treatment of atumor, tumortissue, cancer or metastasis in a subject. The microorganisms or cellsprovidedpreferentially accumulate in tumors, tumor tissues, cancers or metastases. Fordetection and imaging, the microorganisms or cells are modified to expressthat inducesa detectable signal, which can be detected externally to the subject. Themicroorganisms or cells provided also can be employed to treat a tumor, tumortissue,cancer or metastasis and can be modified to express a protein for tumortherapy and/orelimination of a metastatic tumor.
