Burford-Mason A P, MacKay A J, Cummins M, Dardick I
Conacher Laryngeal Laboratory, Toronto Hospital, Ontario, Canada.
Arch Pathol Lab Med. 1994 Oct;118(10):1007-13.
Immunohistochemical detection of proliferating cell nuclear antigen (PCNA), a cell cycle-related protein used to estimate tumor growth fraction, is variable in formalin-fixed compared with methanol-fixed tissue specimens. This is assumed to result from conformational changes in the antigenic epitope induced by formaldehyde; therefore, to be susceptible to retrieval in archival specimens. In this study, formalin fixation reduced the intensity of staining and the number of positive cells to approximately 25% of those in methanol-fixed material. The washing of tissue specimens prior to methacarn fixation also reduced PCNA staining. Loss of staining was not restored after use of a commercial retrieval kit recommended for PCNA immunohistochemistry. Immunoblotting of formalin fixatives and saline washings after removal of tissue specimens consistently demonstrated the presence of PCNA-like activity in solution. We conclude that the exceptional solubility of PCNA is responsible for reduced immunostaining in formalin-fixed material, that the loss is irreversible, and that methanol or methacarn is the fixative of choice for PCNA immunohistochemistry.
增殖细胞核抗原（PCNA）是一种用于评估肿瘤生长分数的细胞周期相关蛋白，与甲醇固定的组织标本相比，在福尔马林固定的标本中，其免疫组织化学检测结果存在差异。这被认为是由甲醛诱导的抗原表位构象变化所致；因此，在存档标本中易于进行抗原修复。在本研究中，福尔马林固定使染色强度和阳性细胞数量降至甲醇固定材料的约25%。在甲醇-氯仿固定之前对组织标本进行冲洗也会降低PCNA染色。使用推荐用于PCNA免疫组织化学的市售抗原修复试剂盒后，染色损失并未恢复。在去除组织标本后，对福尔马林固定剂和盐水冲洗液进行免疫印迹，始终证明溶液中存在PCNA样活性。我们得出结论，PCNA的特殊溶解性导致福尔马林固定材料中免疫染色减少，这种损失是不可逆的，并且甲醇或甲醇-氯仿是PCNA免疫组织化学的首选固定剂。
