Immunohistochemistry: applications to the evaluation of lung and pleural neoplasms: part 2

Our plain-English summary of Immunohistochemistry: applications to the evaluation of lung and pleural neoplasms: part 2, by H. Mani, D.S. Zander (Chest, 2012).

The study

• Authors: H. Mani, D.S. Zander
• Journal: Chest
• Published: 2012;142(5):1324-1333
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Immunohistochemistry has come to occupy a key position among the armamentarium of tools pathologists apply to the evaluation of lung and pleural neoplasms. This technique uses antibodies that bind to specific antigens, usually proteins, enabling microscopic detection of the antigens. Over the last several decades, an impressive array of antibodies has become commercially available, and many of these antibodies have become integrated into the routine practice of pathology. Evaluation of tissue or cytology samples with these antibodies can facilitate determination of tumor type and site of origin. Comments citing results of immunohistochemical staining with these antibodies frequently appear in pathology reports and may be difficult to translate for those less familiar with the technique. This review presents, in two parts, common diagnostic applications of immunohistochemistry with information about strategies taken for frequently encountered differential diagnostic scenarios. This article is the second of the two parts and focuses on immunohistochemical approaches to differentiating primary pulmonary from metastatic adenocarcinomas, mesotheliomas from carcinomas, and various types of spindle cell neoplasms. Potential future directions involving therapeutic and prognostic biomarkers are also discussed.

In plain English

This article is a narrative review, the second of two parts. It reported no new patient data. Instead it summarized published studies on how immunohistochemistry (staining tissue with antibodies that detect specific proteins) helps pathologists classify lung and pleural tumors. It covered three main questions: telling primary lung adenocarcinoma from cancer that spread from elsewhere, telling epithelioid mesothelioma from adenocarcinoma or squamous cell carcinoma, and sorting spindle cell tumors, including sarcomatoid mesothelioma. The authors described using a panel of two or more mesothelial markers and two or more adenocarcinoma markers. They noted that no stain reliably separates mesothelial hyperplasia from malignant mesothelioma. They also noted that sarcomatoid mesothelioma can stain for smooth muscle actin, which could lead to a misdiagnosis of leiomyosarcoma if cytokeratin stains are not done. The authors concluded that immunohistochemistry has proven invaluable for these distinctions and that its role in treatment and prognosis is growing. They cautioned that individual cases may not follow the typical staining patterns. The article does not discuss asbestos.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: narrative review (part 2 of a two-part review)
• Who was studied: No study population of its own; a review of published pathology studies of tumors of the lung and pleura
• Main results:
  • The review described a panel of two or more mesothelial markers and two or more adenocarcinoma markers as usually enough to classify a pleural tumor with epithelioid features as mesothelioma or adenocarcinoma.
  • The authors stated that, despite extensive investigation, no immunostain can reliably tell mesothelial hyperplasia from malignant mesothelioma.
  • The review cited a study by Ordóñez of epithelioid pleural mesotheliomas and lung adenocarcinomas. In that study 100% of mesotheliomas stained for calretinin, CK5/CK6 and mesothelin. Among the lung adenocarcinomas, 8% stained for calretinin, 2% for CK5/CK6 and none for WT1.
  • The review cited a study in which D2-40 stained 86.7% of sarcomatoid mesotheliomas and 25.9% of pulmonary sarcomatoid carcinomas.
  • The review noted that sarcomatoid mesothelioma may stain for smooth muscle actin in up to 60% of cases. This could lead to a misdiagnosis of leiomyosarcoma if cytokeratin stains are not performed.
  • For mesothelioma versus squamous cell carcinoma, the review reported Ordóñez's suggestion to combine two positive mesothelioma markers (WT1 and calretinin or mesothelin) with two negative ones (p63 and MOC-31).
• The authors' conclusion: The authors concluded that immunohistochemistry has enhanced pathologists' ability to resolve diagnostic questions, including telling mesotheliomas from carcinomas, and that its role in therapy and prognosis is growing.
• Limitations the authors state:
  • The authors noted that isolated cases may not behave according to the typical staining patterns they describe.
  • The authors noted that the staining profiles of different spindle cell tumors can overlap.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer.

Medical terms in this study, explained in our Lexicon: Immunohistochemistry, Neoplasm, Pathology, Cytology, Pathology Report, Adenocarcinoma, Mesothelioma, Carcinoma.

Related studies

• Application of immunohistochemistry in the diagnosis of epithelioid mesothelioma: a review and update — N.G. Ordóñez (2013)
• Challenges and controversies in the diagnosis of mesothelioma: Part 1. Cytology-only diagnosis, biopsies, immunohistochemistry, discrimination between mesothelioma and reactive mesothelial hyperplasia, and biomarkers — D.W. Henderson, G. Reid, et al. (2013)
• Diagnostic application of BAP1 immunohistochemistry to differentiate pleural mesothelioma from metastatic pleural tumours — M. Yoshimura, Y. Kinoshita, et al. (2017)
• Evaluation of MTAP immunohistochemistry loss of expression in ovarian serous borderline tumors as a potential marker for prognosis and progression — N. Nilforoushan, N.A. Moatamed (2020)
• BAP1 Immunohistochemistry and p16 FISH in the Diagnosis of Sarcomatous and Desmoplastic Mesotheliomas — H.C. Hwang, S. Pyott, et al. (2016)
• Immunohistochemistry in the distinction between malignant mesothelioma and pulmonary adenocarcinoma: a critical evaluation of new antibodies — A.S. Abutaily, B.J. Addis, et al. (2002)

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