Mesothelin is a differentiation antigen that was first described as the antigenic target of the monoclonal antibody K1.

Expression in normal cells

 normal mesothelial cells

Expression in tumors

 mesotheliomas

• epithelial mesotheliomas (100%)

 nonmucinous ovarian carcinomas
 lung adenocarcinoma (40%)

 nonmucinous carcinomas of the ovary

• serous
• endometrioid
• clear cell
• transitional cell carcinoma

 adenocarcinomas of the pancreas (12 of 14)
 adenocarcinomas of the ampulla of Vater (3 of 3)
 adenocarcinomas of the endometrium (7 of 11)
 adenocarcinomas of the lung (14 of 34)
 cholangiocarcinoma

References

 Ordonez NG. Application of mesothelin immunostaining in tumor diagnosis. Am J Surg Pathol. 2003 Nov;27(11):1418-28. PMID: #14576474#

 Frierson HF Jr, Moskaluk CA, Powell SM, Zhang H, Cerilli LA, Stoler MH, Cathro H, Hampton GM. Large-scale molecular and tissue microarray analysis of mesothelin expression in common human carcinomas. Hum Pathol. 2003 Jun;34(6):605-9. PMID: #12827615#