ABCC2 brush-border expression predicts outcome in papillary renal cell carcinoma: a multi-institutional study of 254 cases.

AIMS: Papillary renal cell carcinoma (PRCC) histologic subtyping is no longer recommended in the 2022 WHO classification. Currently, WHO/ISUP nucleolar grade is the only accepted prognostic histologic parameter for PRCC. ABCC2, a renal drug transporter, has been shown to significantly predict outcomes in PRCC. In this study we evaluated the prognostic significance of ABCC2 IHC staining patterns in a large, multi-institutional PRCC cohort and assessed the association of these patterns with ABCC2 mRNA expression. METHODS AND RESULTS: We assessed 254 PRCCs for ABCC2 IHC reactivity patterns that were stratified into negative, cytoplasmic, brush-border <50%, and brush-border ≥50%. RNA in situ hybridization (ISH) was used to determine the transcript level of each group. Survival analysis was performed with SPSS and GraphPad software. RNA-ISH showed that the ABCC2 group with any brush-border staining was associated with a significant increase in the transcript level, when compared to the negative/cytoplasmic group (P = 0.034). Both ABCC2 groups with brush-border <50% (P = 0.024) and brush-border ≥50% (P < 0.001) were also associated with worse disease-free survival (DFS) in univariate analysis. Multivariate analysis showed that only ABCC2 IHC brush-border (<50% and ≥50%) reactivity groups (P = 0.037 and P = 0.003, respectively), and high-stage disease (P < 0.001) had a DFS of prognostic significance. In addition, ABCC2 brush-border showed significantly worse DFS in pT1a (P = 0.014), pT1 (P = 0.013), ≤4 cm tumour (P = 0.041) and high stage (P = 0.014) groups, while a similar analysis with high WHO/ISUP grade in these groups was not significant. CONCLUSION: ABCC2 IHC brush-border expression in PRCC correlates with significantly higher gene expression and also independently predicts survival outcomes.

Intersecting Pathologies: A Case Report on the Co-presentation of Quasi-Moyamoya Disease and Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal Plasma Cell Disorder, and Skin Changes (POEMS) Syndrome.

Moyamoya disease (MMD) is a rare chronic vasculopathy characterized by progressive stenosis of the internal carotid arteries and the formation of fragile collateral vessels in the brain. Polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes (POEMS) syndrome is a rare paraneoplastic syndrome with a complex presentation that includes polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes. Here, we report a unique case of a 54-year-old male with MMD presenting with recurrent speech loss and mumbling, later diagnosed with POEMS syndrome. Initial imaging revealed Moyamoya vasculopathy, confirmed by computed tomographic angiography (CTA) and magnetic resonance imaging (MRI). Further examination revealed polyneuropathy, organomegaly, and elevated vascular endothelial growth factor (VEGF), meeting the diagnostic criteria for POEMS syndrome. The patient was treated with a cyclophosphamide-bortezomib-dexamethasone regimen, followed by the addition of daratumumab, resulting in clinical improvement. This case highlights the importance of thorough diagnostics and a multidisciplinary treatment approach for patients with complex comorbidities, emphasizing the need for early detection and targeted therapy in managing dual pathologies of MMD and POEMS syndrome.