Department of Laboratory Medicine and Pathobiology, University of Toronto, 27 King's College Circle, Toronto, Ontario, M5S 1A1, Canada.
Hunter Medical Research Institute, Newcastle, New South Wales, Australia.
BMC Cancer. 2020 Apr 3;20(1):272. doi: 10.1186/s12885-020-06733-4.
Clear cell renal cell carcinoma (ccRCC) is a markedly heterogeneous disease in many aspects, including the tumour microenvironment. Our previous study showed the importance of the tumour microenvironment in ccRCC xeno-transplant success rates. In order to better understand the potential relationship between TICs and the immune microenvironment, we employed a multi-modal approach, examining RNA and protein expression (flow cytometry, immunohistochemistry).
We first examined the gene expression pattern of 18 stem/progenitor marker genes in the cancer genome atlas (TCGA) ccRCC cohort. Flow cytometry was next employed to examine lineage-specific expression levels of stem/progenitor markers and immune population makeup in six, disaggregated, primary ccRCC specimens. Immunohistochemistry was performed on a commercial ccRCC tissue microarray (TMA).
The 18 genes differed with respect to their correlation patterns with one another and to their prognostic significance. By flow cytometry, correlating expression frequency of 12 stem/progenitor markers and CD10 resulted in two clusters-one with CD10 (marker of proximal tubular differentiation), and second cluster containing mostly mesenchymal stem cell (MSC) markers, including CD146. In turn, these clusters differed with respect to their correlation with different CD45 lineage markers and their expression of immune checkpoint pathway proteins. To confirm these findings, four stem/progenitor marker expression patterns were compared with CD4, CD8 and CD20 in a ccRCC TMA which showed a number of similar trends with respect to frequency of the different tumour-infiltrating leukocytes.
Taken together, we observed heterogeneous but patterned expression levels of different stem/progenitor markers. Our results suggest a non-random relationship between their expression patterns with the immune microenvironment populations in ccRCC.
透明细胞肾细胞癌（ccRCC）在许多方面存在明显的异质性，包括肿瘤微环境。我们之前的研究表明肿瘤微环境在 ccRCC 异种移植成功率中的重要性。为了更好地理解 TICs 与免疫微环境之间的潜在关系，我们采用了多模态方法，检查了 RNA 和蛋白质表达（流式细胞术、免疫组织化学）。
我们首先检查了癌症基因组图谱（TCGA）ccRCC 队列中 18 个干细胞/祖细胞标记基因的基因表达模式。接下来，我们使用流式细胞术检查了六个分离的原发性 ccRCC 标本中干细胞/祖细胞标记物的谱系特异性表达水平和免疫群体组成。我们在商业 ccRCC 组织微阵列（TMA）上进行了免疫组织化学。
这 18 个基因在彼此之间的相关性模式以及与预后意义方面存在差异。通过流式细胞术，对 12 个干细胞/祖细胞标记物和 CD10 的相关表达频率进行分析，结果分为两个簇，一个簇含有 CD10（近端肾小管分化的标志物），第二个簇包含大多数间充质干细胞（MSC）标志物，包括 CD146。反过来，这些簇在与不同的 CD45 谱系标志物的相关性以及免疫检查点途径蛋白的表达方面存在差异。为了证实这些发现，我们在 ccRCC TMA 中比较了四个干细胞/祖细胞标记物的表达模式与 CD4、CD8 和 CD20，结果显示在不同肿瘤浸润白细胞的频率方面存在许多相似的趋势。
综上所述，我们观察到不同干细胞/祖细胞标记物的表达水平存在异质性，但具有一定的模式。我们的结果表明，它们的表达模式与 ccRCC 中的免疫微环境群体之间存在非随机关系。
