title: Folate receptor alpha expression in lung cancer: diagnostic and prognostic significance.
abstract: With the advent of targeted therapies directed towards folate receptor alpha, with several such agents in late stage clinical development, the sensitive and robust detection of folate receptor alpha in tissues is of importance relative to patient selection and perhaps prognosis and prediction of response. The goal of the present study was to evaluate the expression of folate receptor alpha in non-small cell lung cancer specimens to determine its frequency of expression and its potential for prognosis. The distribution of folate receptor alpha expression in normal tissues as well as its expression and relationship to non-small cell lung cancer subtypes was assessed by immunohistochemistry using tissue microarrays and fine needle aspirates and an optimized manual staining method using the recently developed monoclonal antibody 26B3. The association between folate receptor alpha expression and clinical outcome was also evaluated on a tissue microarray created from formalin fixed paraffin embedded specimens from patients with surgically resected lung adenocarcinoma. Folate receptor alpha expression was shown to have a high discriminatory capacity for lung adenocarcinomas versus squamous cell carcinomas. While 74% of adenocarcinomas were positive for folate receptor alpha expression, our results found that only 13% of squamous cell carcinomas were FRA positive (p<0.0001). In patients with adenocarcinoma that underwent surgical resection, increased folate receptor alpha expression was associated with improved overall survival (Hazard Ratio 0.39, 95% CI 0.18-0.85). These data demonstrate the diagnostic relevance of folate receptor alpha expression in non-small cell lung cancer as determined by immunohistochemistry and suggest that determination of folate receptor alpha expression provides prognostic information in patients with lung adenocarcinoma.
authors.affiliation: Department of Diagnostics Development, Morphotek, Inc., Exton, PA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: O'Shannessy
authors.affiliation: Department of Pathology, University of Pennsylvania School of Medicine, Philadelphia, PA.
authors.forename: Gordon
authors.initials: G
authors.lastname: Yu
authors.affiliation: Laboratory Corporation of America, Los Angeles, CA.
authors.forename: Robert
authors.initials: R
authors.lastname: Smale
authors.affiliation: Laboratory Corporation of America, Los Angeles, CA.
authors.forename: Yao-Shi
authors.initials: YS
authors.lastname: Fu
authors.affiliation: Department of Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA.
authors.forename: Sunil
authors.initials: S
authors.lastname: Singhal
authors.affiliation: Thiel Statistical Consulting, Oxford, CT.
authors.forename: Robert P
authors.initials: RP
authors.lastname: Thiel
authors.affiliation: Department of Diagnostics Development, Morphotek, Inc., Exton, PA.
authors.forename: Elizabeth B
authors.initials: EB
authors.lastname: Somers
authors.affiliation: Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA.
authors.forename: Anil
authors.initials: A
authors.lastname: Vachani
mesh_terms: D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis* / Q000401:mortality* / Q000601:surgery; D003937:Diagnosis, Differential; D005260:Female; D058975:Folate Receptor 1 / Q000235:genetics / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000401:mortality* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D040081:Protein Array Analysis; D016019:Survival Analysis
chemical_list: D058975:Folate Receptor 1