Only eight trials (Slebos et al, 1990; Kern et al, 1994; Silini et al, 1994; Rosell et al, 1995a; Cho et al, 1997; Fukuyama et al, 1997; Rodenhuis et al, 1997; Siegfried et al, 1997) were included because the selection criteria of the studies were different from ours: the search for studies ended in 1997, only trials documenting KRAS2 mutation by PCR (and not those with IHC) were included, other histologies than NSCLC were excluded, 2-year survival rates had to be described. The gene discussed is KRAS; the disease is non-small cell lung carcinoma.