Precision Treatment of Metachronous Multiple Primary Malignancies Based on Constructing Patient Tumor-Derived Organoids.

When a patient has two or more primary tumors, excluding the possibility of diffuse, recurrent, or metastatic, they can be defined as having multiple primary malignant neoplasms (MPMNs). Moreover, cases of three primary urinary tract tumors are very rare. Here, we reported a patient of MPMNs with four primary tumors, including three urinary tract cancers (renal cancer, prostate cancer, and bladder cancer) and lung cancer. The four tumors appeared over 13 years, and pathological results confirmed that they were all primary tumors after different surgeries. In addition, we established patient-derived organoids (PDOs) by collecting tumor specimens. Hematoxylin-eosin (H&E) staining of PDOs showed that the organoids were histopathological consistent with parental tumor. Immunohistochemistry showed that PDOs can also reflect the expression of pathological markers in patients. At the same time, PDOs may also serve as "avatars" of patients to predict sensitivity to different drugs. In summary, we reported a case of MPMNs with four primary tumors and established PDOs from its tumor specimens. A personalized treatment strategy was established based on the histopathological characteristics of the organoids.