Expression of calretinin by breast carcinoma and the potential for misdiagnosis of mesothelioma

Abstract

Fifteen per cent of breast carcinomas stain with calretinin. These tumours are more likely to be high-grade, ER-negative, and display a basal-like phenotype. These tumours may be misdiagnosed as malignant mesothelioma when they metastasize to the pleura.

Application of immunohistochemistry in the diagnosis of epithelioid mesothelioma: a review and update

“…ER and PR can also be useful because these markers are usually absent in mesotheliomas but can be expressed in breast carcinomas. It should be mentioned, however, that basal-like breast carcinomas are negative for both of these markers and that these tumors frequently express calretinin and keratin 5/6 [23,24], 2 of the positive mesothelioma markers that are often used in distinguishing epithelioid mesotheliomas from metastatic adenocarcinomas. Therefore, calretinin and keratin 5/6 are not considered useful markers in discriminating between epithelioid mesotheliomas and breast carcinomas.…”

“…Since squamous cell carcinomas usually express keratin 5/6 and the reaction is often strong and diffuse, this marker has no value in distinguishing between these tumors and mesotheliomas [33]. In addition, because breast carcinomas, especially basal-like breast carcinomas, are frequently keratin 5/6 positive, immunostaining for this marker has no utility in distinguishing epithelioid mesotheliomas from breast carcinomas [23,24,34,42]. Aside from D5/16B4, other antibodies that react with either keratin 5 and/or 6 have become commercially available.…”

“…In addition, it should be emphasized that there are differences in calretinin expression among different types of carcinomas. The percentage of calretinin expression reported has ranged from 6% to 23% in lung adenocarcinomas [2,9,11,17,19,20], 31% to 38% in serous carcinomas [18,21,22], 15% to 74% in breast carcinomas [23,24], and 0% to 10% in renal cell carcinomas [21,[25][26][27]. Other carcinomas that have been reported to be calretinin positive include squamous cell carcinomas of the lung (23%-40%) [2,6,26,28,29] and small cell lung carcinomas (41%-49%) [26,28], 2 tumors that, when they involve the pleura, can potentially be confused with mesothelioma [29,30].…”

Utility of Immunohistochemistry in the Diagnosis of Pleuropulmonary and Mediastinal Cancers: A Review and Update

“…94,99,100 All mesothelial markers also exhibit variable immunoreactions to different carcinomas. A number of studies demonstrate that calretinin positivity can be seen in 6% to 23% of lung ADCs, 94,96 15% to 74% of breast carcinomas, 101,102 23% to 40% of SCCs, 93,103 41% to 49% of SCLCs of lung, and 0% to 10% of renal cell carcinomas. 100,104 Podoplanin appears to be one of the most specific mesothelial markers in differentiating epithelioid mesothelioma from metastatic ADC.…”

“…carcinomas, 106 67% to 100% of SCCs of lung, 102 and 100% of pancreas and colon carcinomas; 106,107 it stains 2% to 15% of epithelioid mesotheliomas in small areas and sparse cells. 94 Epithelial cell adhesion molecule antibody (Ber-Ep4) is another popular marker used in this situation that shows 91% to 100% positivity for ADC of lung, 74% to 100% positivity for SCC, and 13% to 26% positivity for epithelioid mesothelioma 99,108,109 ( Figure 7, a and b).…”