Expression status of folate receptor alpha is significantly correlated with prognosis in non-small-cell lung cancers.
BACKGROUND
To evaluate the prognostic value of folate receptor alpha (FOLR1) and/or reduced folate carrier (RFC1) expression, which are well-characterized folate transporters, in completely resected non-small-cell lung cancer (NSCLC).


METHODS
We quantitatively examined gene expression of FOLR1 and RFC1 in surgical specimens resected from NSCLC patients. A total of 119 consecutive patients from January 2003 to June 2004 were included.


RESULTS
In adenocarcinoma, the FOLR1 gene expression was downregulated in smokers and male patients (P = 0.006 and P < 0.001, respectively). In addition, FOLR1 expression values in patients with well-differentiated, early p-stage, pT1, pN0, EGFR mutant, and p53 wild-type cancers were significantly higher than those for poorly differentiated, advanced p-stage, pT2-4, pN1-3, EGFR wild-type, and p53 mutant (P < 0.001, P < 0.001, P < 0.001, P = 0.002, P < 0.001 and P = 0.023, respectively). In squamous cell carcinoma, FOLR1 expression values in patients with pN1-3 was significantly higher than those with pN0 (P = 0.037). Moreover, the 3-year survival rate and disease-free survival rate of high-FOLR1-expressing patients (94.7% and 75.4%) were significantly higher than those of low-FOLR1-expressing patients (80.9% and 60.8%) (P = 0.008 and P = 0.038). A multivariate analysis confirmed that high FOLR1 expression was an independent and significant factor predicting a favorable prognosis (P = 0.043).


CONCLUSIONS
Higher levels of FOLR1 appear to be associated with better prognoses for patients with lung adenocarcinomas.
Iwakiri
Shotaro
S
Department of Thoracic Surgery, Faculty of Medicine, Kyoto University, Shogoin-Kawara-cho 54, Sakyo-ku, Kyoto, 606-8507, Japan.
Sonobe
Makoto
M
Nagai
Shinjiro
S
Hirata
Toshiki
T
Wada
Hiromi
H
Miyahara
Ryo
R
D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics* / Q000601:surgery; D002352:Carrier Proteins / Q000235:genetics*; D005260:Female; D058975:Folate Receptor 1; D058973:Folate Receptors, GPI-Anchored; D015870:Gene Expression; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011956:Receptors, Cell Surface / Q000235:genetics*
D002352:Carrier Proteins; C548696:FOLR1 protein, human; D058975:Folate Receptor 1; D058973:Folate Receptors, GPI-Anchored; D011956:Receptors, Cell Surface