Mesothelinexpressing

Mesothelinexpressing refers to cells or tissues that express mesothelin, a cell-surface glycoprotein encoded by the MSLN gene. Mesothelin is normally expressed by mesothelial cells lining the pleura, peritoneum, and pericardium, but at relatively low levels in most healthy tissues. In various cancers, mesothelin expression is markedly increased, making it a focus of diagnostic and therapeutic research.

In oncology, mesothelin overexpression has been documented in mesothelioma and in several carcinomas, including pancreatic adenocarcinoma, ovarian serous carcinoma, and subset of lung and gastric cancers. Tumors may be described as mesothelin-expressing when detected by immunohistochemistry, flow cytometry, or RNA-based methods. The level and pattern of expression can vary between tumors and within tumor tissue.

Clinical relevance includes both diagnostic and potential prognostic implications. Immunohistochemical detection of mesothelin can aid in characterizing pleural or peritoneal effusions and in distinguishing mesothelioma from metastatic adenocarcinomas in some settings, though mesothelin is not perfectly specific. Serum levels of soluble mesothelin-related peptide (SMRP) have been studied as a non-invasive biomarker for mesothelioma, but SMRP alone is not sufficient for diagnosis due to limitations in sensitivity and specificity.

Therapeutically, mesothelin is an attractive target because it is variably expressed on several cancers and limited in most normal tissues. Multiple approaches—monoclonal antibodies, antibody-drug conjugates, vaccines, and mesothelin-targeted CAR T cells—have been investigated in preclinical studies and clinical trials. While some trials show activity, challenges include toxicity and heterogeneous expression, underscoring the need for reliable patient selection and combination strategies.