Expression of carbonic anhydrase IX as a novel diagnostic marker for differentiating pleural mesothelioma from non-small cell lung carcinoma

Background and objectives

Mesothelioma is an aggressive tumor with a poor prognosis. Histological diagnosis of mesothelioma using limited tissue samples can be challenging. Carbonic anhydrase IX (CAIX) is a transmembrane protein that is overexpressed in a variety of solid tumors. This study aimed to investigate the clinical utility of CAIX expression in the differential diagnosis of pleural mesothelioma from non-small cell lung carcinoma (NSCLC).

Methods

Unstained tissue microarray slides composed of 56 cases of pleural mesothelioma and 82 cases of NSCLC were subjected to immunohistochemical staining using a mouse anti-human antibody against CAIX.

Results

Of the 38 epithelioid mesothelioma cases, 34 (89%) displayed diffuse and strong cytoplasmic membrane reactivity, while the remaining four cases (11%) showed weak to moderate staining in tumor cells. Five out of sixteen (5/16) sarcomatoid mesothelioma cases were negative. Among the non-small cell lung carcinoma cases, 76% (32/42) of adenocarcinomas and 57% (21/37) of squamous cell carcinomas were completely negative, whereas the remaining cases showed focal weak expression of CAIX.

Conclusions

Our study demonstrates that CAIX expression has a high sensitivity (100%) in detecting pleural epithelioid mesothelioma, which is comparable to or better than currently used mesothelial markers. The specificity of CAIX is within a comparable range to that of commonly used mesothelial markers for differentiating epithelioid mesothelioma from NSCLC. Therefore, we recommend that CAIX immunohistochemistry staining be considered as an additional tool for the differential diagnosis of mesothelioma, particularly pleural epithelioid mesothelioma, from its common mimicker, NSCLC.

Full text

https://www.xiahepublishing.com/2771-165X/JCTP-2024-00029

The study was recently published in the Journal of Clinical and Translational Pathology.

Journal of Clinical and Translational Pathology (JCTP) is the official scientific journal of the Chinese American Pathologists Association (CAPA). It publishes high quality peer-reviewed original research, reviews, perspectives, commentaries, and letters that are pertinent to clinical and translational pathology, including but not limited to anatomic pathology and clinical pathology. Basic scientific research on pathogenesis of diseases as well as application of pathology-related diagnostic techniques or methodologies also fit the scope of the JCTP.

Follow us on X: @xiahepublishing

Follow us on LinkedIn:  Xia & He Publishing Inc.