Abstract: Vitamin C at high concentrations is toxic to cancer cells in vitro. Early clinical studies of vitamin C in patients with terminal cancer suggested clinical benefit, but 2 double-blind, placebo-controlled trials showed none. However, these studies used different routes of administration.

摘要(翻译): 维生素C在高浓度下对体外癌细胞具有毒性。早期对晚期癌症患者进行的维生素C临床研究表明可能有临床益处，但两项双盲、安慰剂对照的试验未显示任何效果。然而，这些研究采用了不同的给药途径。

Abstract: Another sample abstract text goes here.

摘要(翻译): Another translated abstract text goes here.