癌症标记物是血液或组织中的可测量分子，由肿瘤细胞或免疫细胞产生，以应对癌症进展。它们在临床诊断、预后和抗药监测中起着重要作用。尽管DNA、RNA甚至物理影像已经被使用，但蛋白质仍然是最常见的标记物。目前还没有特异性肺癌标记物。转移性肺癌，特别是非小细胞肺癌（NSCLC），是最常见的死因之一。SFPQ、YY1、RTN4、RICTOR、LARP6和HELLS在NSCLC的细胞中的表达水平比对照或炎症性疾病的细胞高。SFPQ在三种细胞类型之间的差异最大。此外，SFPQ的细胞质亚型只存在于晚期癌症中。我们已经开发了ELISAs来检测SFPQ以及长短亚型。证据表明，短亚型主要存在于癌症中。此外，免疫细胞学研究和免疫组化分析显示，SFPQ水平与ELISA结果一致。此外，SFPQ基因的增强DNA甲基化可能促进对比控制和癌细胞之间SFPQ表达差异的了解。考虑到这一点，升高的SFPQ水平和亚型位置可作为癌症诊断和预后标记物。

Cancer markers are measurable molecules in the blood or tissue that are produced by tumor cells or immune cells in response to cancer progression. They play an important role in clinical diagnosis, prognosis, and anti-drug monitoring. Although DNA, RNA, and even physical images have been used, proteins continue to be the most common marker. There are currently no specific markers for lung cancer. Metastatic lung cancer, particularly non-small-cell lung cancer (NSCLC), is one of the most common causes of death. SFPQ, YY1, RTN4, RICTOR, LARP6, and HELLS are expressed at higher levels in cells from NSCLC than in control or cells from inflammatory diseases. SFPQ shows the most difference between the three cell types. Furthermore, the cytoplasmic isoform of SFPQ is only found in advanced cancers. We have developed ELISAs to detect SFPQ and the long and short isoforms. Evidence has shown that the short isoform exists primarily in cancers. Furthermore, immunocytometry studies and IHC analysis have revealed that SFPQ levels are consistent with ELISA results. In addition, enhanced DNA methylation in the SFPQ gene may facilitate the SFPQ expression differences between control and cancer cells. Considering this, elevated SFPQ level and the isoform location could serve as a cancer diagnostic and prognostic marker.