Relationship Between Circulating Tumor Cell Cultures' Treatment Response and Clinical Outcomes

Inclusion Criteria: * Patients with a metastatic solid tumor malignancy with either liver and/or lung metastasis. Patients with newly diagnosed metastatic disease who have not had systemic therapy or are progressing on systemic therapy fitting one of the following cohorts: * Patients had a tumor or liquid biopsy with molecular analysis (genomic analysis or other type of molecular characterization) resulting in a therapeutic target with planned targeted therapy by the patient's treating physician. * Gastric cancer patients who have failed the first and second line chemotherapy. * Bladder cancer patients (with liver and/or lung metastasis) who will receive systemic treatment. * Scheduled to initiate systemic treatment for management of their disease. The systemic treatment will be either cytotoxic chemotherapy or targeted therapy but not checkpoint inhibitor immunotherapy. * ≥18 years of age * Written informed consent obtained and signed * Able to have blood collection without excessive difficulty Exclusion Criteria: * Patient unwilling or unable to complete informed consent * Currently pregnant or lactating women * Physical or psychological inability to complete sample collection for any reason including but not limited to: inability to tolerate any study procedures, any physical limitation that would undermine the safety of the subject in the study, or any psychiatric or neurological condition that inhibits full comprehension of study requirements and inability to complete informed consent, as determined by treating physician