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).
NSCLC overexpressed FRα and RFC1.In a multivariate analysis, lung adenocarcinomas were more likely to express FRα in the cytoplasm (OR = 4.39; p < 0.0001) and membrane (OR = 5.34; p < 0.0001) of malignant cells than squamous cell carcinomas.
Two sets of array-based data retrieved from the Gene Expression Omnibus consistently showed that expression of FOLR1, a folate transport enzyme, and GGH, an enzyme that prevents folate retention, were higher and lower, respectively, in adenocarcinomas compared to SCC.