Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan.
Department of Diagnostic Pathology, National Hospital Organization Kyoto Medical Center, Kyoto, Japan.
Thorac Cancer. 2019 May;10(5):1188-1192. doi: 10.1111/1759-7714.13062. Epub 2019 Apr 7.
Small cell lung cancer (SCLC) is normally diagnosed with hematoxylin and eosin stains, although some cases require immunohistochemistry (IHC). P40 is highly sensitive and specific for squamous cell carcinoma and is thus considered the best marker for this cancer. However, the status of p40 expression in SCLC is not well known. The aim of this study was to analyze p40 expression in resected SCLC using IHC.
Forty-four surgically resected SCLC cases were enrolled. Clinical data were obtained from the patients' medical records. Pathologists blinded to the patients' clinical data reviewed the SCLC slides. IHC was performed on a representative slide of each case.
Although p40 was not diffusely expressed in any of the SCLC cases, p40-positive cells were observed in the tumors in 15 cases (34.1%). Ten of these exhibited p40 in < 1% of tumor cells. In the remaining five cases, 1-5% of tumor cells expressed p40, and in three of these, the cells expressing p40 also expressed TTF-1 and neuroendocrine markers. There was no statistically significant relationship between p40 positivity and any other clinicopathological characteristics.
Some resected SCLCs express p40 focally. This result suggests that the presence of positive p40 cells does not exclude a diagnosis of SCLC. Thus, small biopsy or cytology specimens with p40-positive cells must be diagnosed carefully.
小细胞肺癌（SCLC）通常通过苏木精和伊红染色进行诊断，尽管有些病例需要免疫组织化学（IHC）。P40 对鳞状细胞癌高度敏感和特异，因此被认为是这种癌症的最佳标志物。然而，SCLC 中 p40 表达的状态尚不清楚。本研究旨在通过 IHC 分析切除的 SCLC 中 p40 的表达。
纳入 44 例手术切除的 SCLC 病例。临床数据来自患者的病历。病理学家在不了解患者临床数据的情况下对 SCLC 切片进行了审查。对每个病例的代表性切片进行了 IHC。
尽管在任何 SCLC 病例中 p40 均未弥漫表达，但在 15 例肿瘤中观察到 p40 阳性细胞（34.1%）。其中 10 例肿瘤细胞中 p40 的表达<1%。在其余 5 例中，有 1-5%的肿瘤细胞表达 p40，其中 3 例表达 p40 的细胞也表达 TTF-1 和神经内分泌标志物。p40 阳性与任何其他临床病理特征之间无统计学显著关系。
一些切除的 SCLC 局灶性表达 p40。这一结果表明，存在阳性 p40 细胞并不排除 SCLC 的诊断。因此，必须仔细诊断 p40 阳性细胞的小活检或细胞学标本。
