Objective:To summarize the clinical and pathological characteristics, treatment methods, and prognosis of papillary renal neoplasm with reverse polarity (PRNRP).Methods:The clinical and pathological data of six pathologically confirmed PRNRP patients admitted to Renji Hospital affiliated with Shanghai Jiaotong University School of Medicine from August 2022 to August 2023 were retrospectively analyzed. Among them, three were male and three were female, with an average age of (55.3±10.5) years old. All six cases were incidentally discovered during health examinations. Preoperative contrast-enhanced CT scans showed tumors with cortical phase manifestations of uneven enhancement, avascularity, and indistinct borders, with CT values of (85.6±18.7) HU. In the corticomedullary phase, the CT values showed mild elevation, with an average of (94.3±4.7) HU. In the delayed phase, the tumor boundaries were clear, and the enhancement degree was significantly lower than that of the surrounding renal cortex and medulla, with a tumor CT value of (86.3±11.9) HU. The pseudocapsule of the tumor was not clearly displayed on contrast-enhanced CT scans. All cases underwent partial nephrectomy, including two cases of robot-assisted laparoscopic partial nephrectomy and four cases of laparoscopic partial nephrectomy.Results:Postoperative pathological measurements revealed a maximum tumor diameter ranging from 6 to 15 mm, with an average diameter of (11.0±3.5) mm. All six cases were classified as pT 1aN 0M 0 stage. Microscopically, the tumors exhibited branching papillary structures with eosinophilic cytoplasm, and the tumor cells displayed low-grade nuclei located at the top of the cytoplasm and away from the basal membrane. Immunohistochemical analysis showed diffuse strong positivity for GATA3 and CK7, while CA-Ⅸ expression was negative. The median follow-up time after surgery was 10(9, 13) months, and no tumor recurrence or metastasis was observed. Conclusions:PRNRP is a rare, low-grade malignant papillary renal tumor. Contrast-enhanced CT scan has characteristic features of avascularity. Pathological morphological features are low-grade nuclei located at the top of the cytoplasm and far away from the basal membrane, forming a "reverse polarity". The immunophenotype shows positive expression of GATA3 and CK7. Partial nephrectomy is the recommended treatment approach, and the postoperative prognosis is favorable.

Lenvatinib, a second-generation multi-receptor tyrosine kinase inhibitor approved by the FDA for first-line treatment of advanced liver cancer, facing limitations due to drug resistance. Here, we applied a multidimensional, high-throughput screening platform comprising patient-derived resistant liver tumor cells (PDCs), organoids (PDOs), and xenografts (PDXs) to identify drug susceptibilities for conquering lenvatinib resistance in clinically relevant settings. Expansion and passaging of PDCs and PDOs from resistant patient liver tumors retained functional fidelity to lenvatinib treatment, expediting drug repurposing screens. Pharmacological screening identified romidepsin, YM155, apitolisib, NVP-TAE684 and dasatinib as potential antitumor agents in lenvatinib-resistant PDC and PDO models. Notably, romidepsin treatment enhanced antitumor response in syngeneic mouse models by triggering immunogenic tumor cell death and blocking the EGFR signaling pathway. A combination of romidepsin and immunotherapy achieved robust and synergistic antitumor effects against lenvatinib resistance in humanized immunocompetent PDX models. Collectively, our findings suggest that patient-derived liver cancer models effectively recapitulate lenvatinib resistance observed in clinical settings and expedite drug discovery for advanced liver cancer, providing a feasible multidimensional platform for personalized medicine.