We conclude that SLC46A1/PCFT and SLC19A1/RFC-1 are associated with DFS of patients with colorectal cancer and hypothesize that poor response to 5-fluorouracil plus leucovorin therapy in some patients may be linked to low expression of these genes.
In conclusion, this is the first study to simultaneously evaluate both DNA methylation and protein expression of all three folate transporter genes, FOLR1, PCFT, and RFC1, in colorectal cancer.
We analyzed mononucleotide repeats in RFC1 and RFC3 in 29 GC with high MSI (MSI-H), 20 GC with low MSI (MSI-L), 45 GC with stable MSI (MSS), 35 CRC with MSI-H, 20 CRC with MSI-L, and 45 CRC with MSS by single-strand conformation polymorphism.
These findings suggest that although the RFC1 80G > A and FOLH1 1561C > T polymorphisms may influence folate status, they are not likely to have a major independent role in the development of colorectal cancer.
Real-time PCR was used to quantify expression levels of folate-associated genes including the reduced folate carrier (RFC-1), folylpolyglutamate synthase (FPGS), gamma-glutamyl hydrolase (GGH),and thymidylate synthase (TS) in tumor tissue and adjacent mucosa of patients with primary colorectal cancer (n=102).