Randomized phase III study of S-1 alone versus S-1 plus Lentinan (LNT) in advanced or recurrent gastric cancer started in February 2007 conducted by the Japanese Foundation for Multidisciplinary Treatment of Cancer. The objective of this study is to evaluate the superiority of S-1/LNT to S-1 alone. The primary end point is to compare over all survival between both treatment groups. Secondary end points include time to treatment failure, the grade and rate of the adverse events, the evaluation of quality of life (QOL), response rate evaluated by RECIST and immunological parameters. QOL is evaluated by Japanese version of FACT-BRM questionnaire. Immunological parameters include serum complements (CH50, C3) and beta-1, 3 binding monocytes. The sample size is estimated at 150 patients per arm. Registration period is 2 years with 2-year follow-up. This study has a chance to prove the efficacy of the non-specific biological response modifier. We will have to cooperate in order to make this study a success.