• All IHC stains will include a positive control tissue

• 100% sensitivity for mesothelial cells and epithelioid mesotheliomas
• In epithelioid mesotheliomas, the staining pattern is usually strong to moderate.
• Generally >50% of mesothelial cells react for the marker. Desmoplastic mesotheliomas will show weak to no reactivity with calretinin
• Is useful in separating epithelioid mesotheliomas from adenocarcinomas particularly when combined with B72.3, CEA, BEREP4 and LeuM1
• Calretinin has been reported to be 81-90% specific for mesothelial cells. In one study 9/40 lung adenocarcinomas, 15/135 breast cancers, and 2/8 pancreatic adenocarcinomas showed positivity for Calretinin. However, the degree of staining in these tumors was much weaker and fewer cells stained than that observed in mesothelial cells. The above findings further substantiate the need for a panel approach when using this marker
• Calretinin is positive in most schwannomas (96%); in contrast, rare neurofibromas (7%) stain for calretinin.
• Other tissue types found to have some degree of reactivity for Calretinin include:

Submit a formalin-fixed, paraffin embedded tissue block

Formalin-fixed, paraffin embedded (FFPE) tissue block

FFPE tissue section mounted on a charged, unstained slide

Ambient (preferred)

• Unlabeled/mislabeled block
• Insufficient tissue
• Slides broken beyond repair

Immunohistochemical staining and microscopic examination

If requested, an interpretive report will be provided

Specifications

• Calretinin is a 29KD calcium binding protein

Staining pattern

• Both cytoplasmic and nuclear staining

References

1. Doglioni C et al: Calretinin: a novel immunocytochemical marker for mesothelioma, AJSP 20(9):1037-1046, 1996.
2. ACTA Cytol 1997; 41(6):1757-1761.
3. Fine S W et al: Immunohistochemical Staining for Calretinin is useful for differentiating Schwannomas from neurofibromas. Am J Clin Pathol 2004; 122: 552-559.