However, a large German study found that neither the MTHFR C677T nor the A1298C polymorphisms were associated with toxicity to 5-FU in cancer patients (Schwab et al, 2008), supporting earlier observations in patients treated with 5-FU monotherapy (Cohen et al, 2003), FOLFOX (Ruzzo et al, 2007) or FOLFIRI (Ruzzo et al, 2008). The gene discussed is MTHFR; the disease is cancer.