Clear cell renal cell carcinoma (ccRCC) is characterized by a high degree of intratumoral heterogeneity (ITH). Besides genomic ITH, there is considerable functional ITH, which encompasses spatial niches with distinct proliferative and signaling activities. The full extent of functional spatial heterogeneity in ccRCC is incompletely understood. In the present study, a total of 17 ccRCC tissue specimens from different sites (primary tumor,n= 11; local recurrence,n= 1; distant metastasis,n= 5) were analyzed using digital spatial profiling (DSP) of protein expression. A total of 128 regions of interest from the tumor periphery and tumor center were analyzed for the expression of 46 proteins, comprising three major signaling pathways as well as immune cell markers. Results were correlated to clinico-pathological variables. The differential expression of granzyme B was validated using conventional immunohistochemistry and was correlated to the cancer-specific patient survival. We found that a total of 37 proteins were differentially expressed between the tumor periphery and tumor center. Thirty-five of the proteins were upregulated in the tumor periphery compared to the center. These included proteins involved in cell proliferation, MAPK and PI3K/AKT signaling, apoptosis regulation, epithelial-to-mesenchymal transition, as well as immune cell markers. Among the most significantly upregulated proteins in the tumor periphery was granzyme B. Granzyme B upregulation in the tumor periphery correlated with a significantly reduced cancer-specific patient survival. In conclusion, this study highlights the unique cellular contexture of the tumor periphery in ccRCC. The correlation between granzyme B upregulation in the tumor periphery and patient survival suggests local selection pressure for aggressive tumor growth and disease progression. Our results underscore the potential of spatial biology for biomarker discovery in ccRCC and cancer in general.
透明细胞肾细胞癌（ccRCC）具有高度的瘤内异质性特征。除基因组异质性外，该肿瘤还存在显著的功能性异质性，表现为具有不同增殖活性和信号转导活性的空间生态位。目前对ccRCC功能性空间异质性的全貌尚未完全阐明。本研究采用数字空间蛋白表达谱分析技术，对来自不同部位的17例ccRCC组织标本（原发灶11例、局部复发灶1例、远处转移灶5例）进行分析。通过对肿瘤边缘区和中心区共128个感兴趣区域进行46种蛋白检测，涵盖三大信号通路及免疫细胞标志物，并将结果与临床病理参数进行关联分析。其中颗粒酶B的差异表达通过传统免疫组化进行验证，并与患者癌症特异性生存期进行相关性分析。研究发现共有37种蛋白在肿瘤边缘区与中心区呈现差异表达，其中35种在边缘区表达上调，涉及细胞增殖、MAPK和PI3K/AKT信号通路、凋亡调控、上皮-间质转化及免疫细胞标志物等相关蛋白。颗粒酶B是肿瘤边缘区上调最显著的蛋白之一，其表达上调与患者癌症特异性生存期显著缩短相关。本研究揭示了ccRCC肿瘤边缘区独特的细胞微环境特征。颗粒酶B在肿瘤边缘区的上调与患者生存期的关联性，提示该区域存在促进肿瘤侵袭性生长和疾病进展的局部选择压力。研究结果凸显了空间生物学在ccRCC乃至整体癌症生物标志物发现领域的应用潜力。
肿瘤(癌症)患者之家