The close association between increased CD57+ lymphocytes and improved survival of patients identified in this study may relate to the following reasons: first, CD57 expression in lymphocytes such as CD8+ T and NK cells correlates with increased expression of cytolytic enzymes such as granzyme A, granzyme B and perforin, suggesting that CD57+ lymphocytes possess the ability to cytolysis target cells including tumor cells [31]. This evidence concerns the gene PRF1 and neoplasm.