Burns Janine A, Li Yuan, Cheney Carol A, Ou Yangsi, Franlin-Pfeifer Laura L, Kuklin Nelly, Zhang Zhi-Qiang
Department of Biologics Research, Merck Research Laboratories, West Point, PA 19486, USA.
J Histochem Cytochem. 2009 Mar;57(3):257-64. doi: 10.1369/jhc.2008.952911. Epub 2008 Nov 11.
Protein phosphorylation is frequently used as an indicator of cellular signaling activity. Elevated phosphorylation of tyrosine kinase receptors plays an important role in cancer pathogenesis. However, phosphoproteins are usually poorly preserved in clinical tissue samples that are routinely fixed in 10% formalin. Nonetheless, in oncology clinical trials, use of phosphoproteins as biomarkers has been considered to be of great value in evaluating the effectiveness of a given drug candidate. Therefore, it is worthy of investigating whether alternative fixatives would improve the preservation of phosphoproteins in tissue. We compared the IHC staining of a number of phosphoproteins in xenograft and human surgical tumor tissues fixed in three different fixatives: 10% formalin, 4% paraformaldehyde (PFA), and Streck's tissue fixative (STF). We found that STF significantly enhanced the staining intensity of phosphoproteins compared with 10% formalin or 4% PFA. STF fixative also showed superiority of preservation of phosphoproteins in human surgical samples. Our results indicate that the choice of fixative could significantly affect the usability of clinical tissue samples for evaluating phosphoprotein by IHC.
蛋白质磷酸化常被用作细胞信号传导活性的指标。酪氨酸激酶受体磷酸化水平升高在癌症发病机制中起重要作用。然而，在常规用10%福尔马林固定的临床组织样本中，磷蛋白通常保存不佳。尽管如此，在肿瘤学临床试验中，将磷蛋白用作生物标志物被认为在评估特定候选药物的有效性方面具有重要价值。因此，研究替代固定剂是否能改善组织中磷蛋白的保存情况是值得的。我们比较了用三种不同固定剂固定的异种移植和人类手术肿瘤组织中多种磷蛋白的免疫组化染色情况，这三种固定剂分别是：10%福尔马林、4%多聚甲醛（PFA）和斯特雷克组织固定剂（STF）。我们发现，与10%福尔马林或4% PFA相比，STF显著增强了磷蛋白的染色强度。STF固定剂在人类手术样本中也显示出在保存磷蛋白方面的优势。我们的结果表明，固定剂的选择可能会显著影响临床组织样本用于免疫组化评估磷蛋白的可用性。
