It has been shown that patients with advanced HCC have an increased frequency of CD4+CD25+ regulatory T cells. These cells might suppress tumor-specific immune responses. Cyclophosphamide has been shown to reduce the frequency of CD4+CD25+ regulatory T cells. The aim of this study is to test if the treatment with cyclophosphamide leads to a decrease in the frequency of CD4+CD25+ regulatory T cells and to increase tumor specific immune responses in patients with advanced HCC.