Papillary renal neoplasm with reverse polarity (PRNRP) is a recently described indolent entity with distinct features and its recognition from other oncocytic/eosinophilic papillary renal cell carcinoma (ePRCC) has important prognostic implications. ABCC2, a renal drug transporter, is overexpressed in aggressive PRCCs. In this study, we compared the clinicopathological parameters and the biological ABCC2 expression between PRNRP and ePRCC. PRNRP (n = 8) and ePRCC (n = 21) cases were selected from resection specimens and corresponding clinicopathological data were collected. ABCC2 immunohistochemical (IHC) staining was performed and ABCC2 staining patterns were classified as negative, cytoplasmic, and brush-border. RNA in-situ hybridization (ISH) was used to assess ABCC2 transcript levels. All eight PRNRP cases had weak cytoplasmic ABCC2 IHC reactivity; however, they showed no detectable ABCC2 transcripts on RNA ISH. In comparison, 76% (16/21) of ePRCCs showed ABCC2 IHC brush-border expression and significantly higher ABCC2 RNA ISH transcript levels (p < 0.001). Additionally, the ePRCC group showed a significantly larger tumor size (p = 0.004), higher WHO/ISUP grade (p < 0.001), and stage (p = 0.044). None of the PRNRP cases showed disease progression, while 9.5% (2/21) ePRCCs had disease progression. PRNRP is clinically and biologically distinct from ePRCC. Hence, it is crucial to differentiate between these two entities, particularly in needle core biopsies.

中文翻译：

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反极性乳头状肾肿瘤在生物学和临床上与嗜酸性乳头状肾细胞癌不同


反极性乳头状肾肿瘤（PRNRP）是最近描述的一种具有独特特征的惰性实体，其与其他嗜酸性/嗜酸性乳头状肾细胞癌（ePRCC）的识别具有重要的预后意义。 ABCC2 是一种肾脏药物转运蛋白，在侵袭性 PRCC 中过度表达。在本研究中，我们比较了 PRNRP 和 ePRCC 的临床病理学参数和生物学 ABCC2 表达。从切除标本中选取PRNRP（ n =8）和ePRCC（ n =21）病例并收集相应的临床病理数据。进行 ABCC2 免疫组织化学 (IHC) 染色，ABCC2 染色模式分为阴性、细胞质和刷状缘。 RNA 原位杂交 (ISH) 用于评估 ABCC2 转录水平。所有 8 个 PRNRP 病例的细胞质 ABCC2 IHC 反应性较弱；然而，他们在 RNA ISH 上没有显示出可检测到的 ABCC2 转录本。相比之下，76% (16/21) 的 ePRCC 显示 ABCC2 IHC 刷状缘表达，并且 ABCC2 RNA ISH 转录物水平显着较高 ( p < 0.001)。此外，ePRCC 组的肿瘤尺寸明显更大 ( p = 0.004)，WHO/ISUP 分级更高 ( p < 0.001) 和分期 ( p = 0.044)。所有 PRNRP 病例均未出现疾病进展，而 9.5% (2/21) ePRCC 出现疾病进展。 PRNRP 在临床和生物学上与 ePRCC 不同。因此，区分这两个实体至关重要，特别是在针芯活检中。