FOLR1 and non-small cell lung carcinoma: A study found that FRα-positive (FRα+) CTC levels were significantly higher in EpCAM-negative (EpCAM−) fractions than in EpCAM-positive (EpCAM+) fractions in NSCLC patients21; this demonstrates that the expression of EpCAM and FRα in NSCLC were heterogeneous.