Background and aims: Brain metastases are prevalent in the late stages of malignant melanoma. Multimodal therapy remains challenging. Patient-derived organoids (PDOs) represent a valuable pre-clinical model, faithfully recapitulating key aspects of the original tumor, including the heterogeneity and the mutational status. This study aimed to establish PDOs from melanoma brain metastases (MBM-PDOs) and to test the feasibility of using them as a model for in vitro targeted-therapy drug testing. Methods: Surgical resection samples from eight patients with melanoma brain metastases were used to establish MBM-PDOs. The samples were enzymatically dissociated followed by seeding into low-attachment plates to generate floating organoids. The MBM-PDOs were characterized genetically, histologically, and immunohistologically and compared with the parental tissue. The MBM-PDO cultures were exposed to dabrafenib (BRAF inhibitor) and trametinib (MEK inhibitor) followed by a cell viability assessment. Results: Seven out of eight cases were successfully cultivated, maintaining the histological, immunohistological phenotype, and the mutational status of the parental tumors. Five out of seven cases harbored BRAF V600E mutations and were responsive to BRAF and MEK inhibitors in vitro. Two out of seven cases were BRAF wild type: one case harboring an NRAS mutation and the other harboring a KIT mutation, and both were resistant to BRAF and MEK inhibitor therapy. Conclusions: We successfully established PDOs from melanoma brain metastases surgical specimens, which exhibited a consistent histological and mutational profile with the parental tissue. Using FDA-approved BRAF and MEK inhibitors, our data demonstrate the feasibility of employing MBM-PDOs for targeted-therapy in vitro testing.

Cholangiocarcinoma is a rare and aggressive cancer type with limited therapeutic options. Several novel antibody–drug conjugates (ADC) have demonstrated promising antitumor activity in solid tumors. This study aimed to investigate the expression and the potential prognostic role of the protein targets of the recently developed ADCs in cholangiocarcinoma. Moreover, the study aimed to establish patient-derived tumor organoids (PDO) and to employ them for in vitro ADC testing. We evaluated the expression of TROP2, NECTIN4, folate receptor 1, HER2, and HER3 via IHC in a cholangiocarcinoma tissue microarray (n = 113) and analyzed the expression level with respect to clinicopathologic parameters. Furthermore, we generated cholangiocarcinoma PDO culture lines and used them to test the antitumor activity of ADCs in vitro. IHC analyses revealed that TROP2 was the most frequently expressed (91% of cases), followed by folate receptor 1 (51%), NECTIN4 (49%), HER3 (20%), and HER2 (7%). TROP2 showed moderate to high expression (H-score ≥100) in 74% of cases. No significant correlations with overall or disease-free survival, tumor grade, or tumor stage were observed. Six cholangiocarcinoma PDO lines were successfully established (55% success rate). All PDO lines expressed TROP2 concordantly with their parental tumors and showed growth inhibition (IC50 = 0.1–0.4 μg/mL) in response to sacituzumab govitecan (TROP2-targeting ADC). This study reveals that TROP2 is widely expressed in cholangiocarcinoma. Moreover, it provides preclinical evidence for the potential of the use of sacituzumab govitecan as a novel therapeutic strategy in treating patients with cholangiocarcinoma.

Background and aims: Brain metastases are prevalent in the late stages of malignant melanoma. Multimodal therapy remains challenging. Patient-derived organoids (PDOs) represent a valuable pre-clinical model, faithfully recapitulating key aspects of the original tumor, including the heterogeneity and the mutational status. This study aimed to establish PDOs from melanoma brain metastases (MBM-PDOs) and to test the feasibility of using them as a model for in vitro targeted-therapy drug testing.Methods: Surgical resection samples from eight patients with melanoma brain metastases were used to establish MBM-PDOs. Samples were enzymatically dissociated followed by seeding into low-attachment plates to generate floating organoids. The MBM-PDOs were characterized genetically, histologically, immunohistologically and compared with the parental tissue. The MBM-PDO cultures were exposed to dabrafenib (BRAF inhibitor) and trametinib (MEK inhibitor) followed by cell viability assessment.Results: Seven out of eight cases were successfully cultivated, maintaining the histological, immunhistological phenotype, and the mutational status of the parental tumors. Five out of seven cases harbored BRAF V600E mutations and were responsive to BRAF and MEK inhibitors in vitro. Two out of seven cases were BRAF wild type, one case harboring an NRAS mutation and the other harboring a KIT mutation, and both were resistant to BRAF and MEK inhibitor therapy. Conclusion:We successfully established PDOs from melanoma brain metastases surgical specimens, which exhibited a consistent histological and mutational profile with the parental tissue. Using FDA-approved BRAF and MEK inhibitors, our data demonstrates the feasibility of employing MBM-PDOs for targeted-therapy in vitro testing.

Complete and incomplete expression patterns of Her2 and Her3 in cholangiocarcinoma.

Expression of CK7 and CA19-9 via immunohistochemistry (IHC) in PDO cultures.

HER2/HER3 IHC scoring criteria following gastric cancer guidelines. A table listing the definition and interpretation of the HER2 and HER3 IHC scoring system.