Shin H J, Kalapurakal S K, Lee J J, Ro J Y, Hong W K, Lee J S
Department of Pathology, University of Texas M. D. Anderson Cancer Center, Houston 77030, USA.
Mod Pathol. 1997 Mar;10(3):224-30.
Because of technical problems in immunohistochemical staining of archival material, antigens can be masked or lost. A recent study reported diminished p53 immunoreactivity in slides that had been sectioned from parafinn-embedded tissue blocks and stored at room temperature. To investigate this issue, we performed immunohistochemical staining with use of a p53 monoclonal antibody (DO7) in 13 head and neck squamous cell carcinoma (HNSCC) and 13 non-small-cell lung carcinomas. The fresh-cut and stored slides were simultaneously stained with and without the use of a microwave heating (MWH) technique, and we compared the results of p53 immunostaining. The stored slides were sectioned from paraffin blocks 4 to 25 years old and kept at room temperature for 6 to 48 months. The slides were blindly evaluated for percentage of positivity and staining intensity. Twelve HNSCCs and six lung carcinomas showed p53 positivity. The stored slides showed a considerable decrease in staining intensity (P = 0.039), compared with fresh-cut slides. The difference in the percentage of positivity between the stored and fresh-cut slides was statistically significant, but the mean value of the difference was only 3.6%, which might not be meaningful for semiquantitation of immunostaining. MWH greatly enhanced staining intensity and percentage of positivity for both stored and fresh-cut slides. When MWH was applied, no significant difference in staining intensity (P = 0.063) was detected in fresh-cut versus stored slides, but the difference in the percentage of positivity was statistically significant (mean value, 3.1%). Individual cases showed a consistent p53 status regardless of the MWH treatment, storage duration, or age of the blocks. This study demonstrated a considerable decrease in p53 immunoreactivity in stored slides. Because the MWH successfully retrieved the p53 antigen without causing a change in p53 status, stored slides combined with an MWH antigen retrieval technique in a metal-containing solution should provide p53 immunostaining results similar to those from fresh-cut slides, as long as staining intensity is not a sole study parameter.
由于存档材料免疫组织化学染色中的技术问题，抗原可能会被掩盖或丢失。最近一项研究报告称，从石蜡包埋组织块切片并在室温下保存的载玻片中，p53免疫反应性降低。为了研究这个问题，我们使用p53单克隆抗体（DO7）对13例头颈部鳞状细胞癌（HNSCC）和13例非小细胞肺癌进行了免疫组织化学染色。新鲜切片和保存后的载玻片同时在使用和不使用微波加热（MWH）技术的情况下进行染色，我们比较了p53免疫染色的结果。保存后的载玻片取自4至25年的石蜡块，在室温下保存6至48个月。对载玻片的阳性百分比和染色强度进行盲法评估。12例HNSCC和6例肺癌显示p53阳性。与新鲜切片相比，保存后的载玻片染色强度显著降低（P = 0.039）。保存后的载玻片与新鲜切片之间阳性百分比的差异具有统计学意义，但差异的平均值仅为3.6%，这对于免疫染色的半定量可能没有意义。MWH极大地增强了保存后的载玻片和新鲜切片的染色强度及阳性百分比。当应用MWH时，新鲜切片与保存后的载玻片在染色强度上未检测到显著差异（P = 0.063），但阳性百分比的差异具有统计学意义（平均值为3.1%）。无论MWH处理、保存时间或组织块年龄如何，个别病例的p53状态一致。本研究表明保存后的载玻片中p53免疫反应性显著降低。由于MWH成功地恢复了p53抗原且未导致p53状态改变，只要染色强度不是唯一的研究参数，在含金属溶液中结合MWH抗原修复技术的保存后的载玻片应能提供与新鲜切片相似的p53免疫染色结果。
