AI 中文总结
本研究通过两个独立的纯度校正胶质母细胞瘤队列，发现MAPK通路活性与PPOX表达呈负相关，为MAPK调控PpIX合成提供了人体组织证据，或可成为增强5-ALA荧光的潜在靶点。
AI 中文摘要
5-氨基乙酰丙酸（5-ALA）可通过原卟啉IX（PpIX）促进胶质母细胞瘤的荧光引导切除，但荧光强度存在显著异质性，限制了边缘区分。细胞系研究显示，MAPK通路激活会通过外排转运体ABCB1的外排增加，以及将PpIX转化为血红素的酶亚铁螯合酶（FECH）的作用，导致PpIX水平降低。然而，该机制尚未在人体组织中开展研究。本研究采用两组独立的纯度校正的原发IDH野生型胶质母细胞瘤标本：TCGA-GBM队列（n=140，发现队列）、CGGA队列（n=87，验证队列），未检测到MAPK信号与其假定下游效应物（ABCB1和FECH）之间存在可重复的相关性。相反，MAPK活性与将原卟啉原IX转化为原卟啉IX的酶PPOX之间存在可重复的负相关：TCGA-GBM队列（n=133个具有纯度估计值的样本，rho=-0.40，95%自助置信区间[-0.54,-0.25]，校正后p<0.001），CGGA队列（rho=-0.28，95%自助置信区间[-0.47,-0.07]，校正后p=0.0342）。该发现对置换检验和纯度校正的替代方法具有稳健性。本研究首次报告了人体组织中该关联的重复验证证据。若该相关性反映因果关系，MAPK对PpIX的调控将发生在合成阶段，而非先前细胞培养研究暗示的清除阶段。本研究还观察到MAPK通路的差异激活：经典亚型中激活增加，原神经亚型中激活减少；MAPK通路激活与总生存期无相关性（log-rank p=0.73）。PPOX表达与MAPK通路激活的关联具有生物学意义而非预后意义，提示MAPK通路是增强5-ALA荧光的潜在靶点。
英文摘要
5-aminolevulinic acid (5-ALA) promotes fluorescence-based resection of glioblastoma via protoporphyrin IX (PpIX); however, there is considerable heterogeneity in fluorescence intensity, limiting margin distinction. Cell-line studies show that stimulation of the MAPK pathway results in decreased PpIX levels through increased elimination by ABCB1, an efflux transporter, and ferrochelatase (FECH), the enzyme that converts PpIX to heme. However, the mechanism has yet to be studied in human tissue. Using two independent, purity-adjusted sets of primary IDH-wildtype glioblastoma specimens (TCGA-GBM, n=140, discovery; CGGA, n=87, validation), no reproducible correlation between MAPK signaling and its proposed downstream effectors (ABCB1 and FECH) could be detected. Instead, MAPK activity displayed a reproducibly negative relationship with PPOX, the enzyme that converts protoporphyrinogen IX to protoporphyrin IX: TCGA-GBM (n=133 with purity estimates; rho = -0.40, 95% bootstrap CI [-0.54, -0.25], adjusted p < 0.001), CGGA (rho = -0.28, 95% bootstrap CI [-0.47, -0.07], adjusted p = 0.0342). The finding was robust to permutation testing and to alternative approaches to purity adjustment. Here we report, for the first time, replicated human-tissue evidence for this association. If this correlation reflects causality, MAPK regulation of PpIX would act at the point of synthesis rather than at the clearance steps implied by previous cell-culture studies. We observed differential activation of the MAPK pathway with increased activation in the classical subtype and decreased activation in the proneural subtype. There was no correlation between MAPK pathway activation and overall survival (log-rank p = 0.73). The association between PPOX expression and MAPK pathway activation is biological rather than prognostic, identifying the MAPK pathway as a candidate handle for increasing 5-ALA fluorescence.
Comments16 pages, 5 figures, 2 tables
