L-fucose, a sugary regulator of antitumor immunity and immunotherapies.

l-fucose is a dietary sugar that is used by cells in a process called fucosylation to posttranslationally modify and regulate protein behavior and function. As fucosylation plays essential cellular functions in normal organ and immune developmental and homeostasis, it is perhaps not surprising that it has been found to be perturbed in a number of pathophysiological contexts, including cancer. Increasing studies over the years have highlighted key roles that altered fucosylation can play in cancer cell-intrinsic as well as paracrine signaling and interactions. In particular, studies have demonstrated that fucosylation impact tumor:immunological interactions and significantly enhance or attenuate antitumor immunity. Importantly, fucosylation appears to be a posttranslational modification that can be therapeutically targeted, as manipulating the molecular underpinnings of fucosylation has been shown to be sufficient to impair or block tumor progression and to modulate antitumor immunity. Moreover, the fucosylation of anticancer agents, such as therapeutic antibodies, has been shown to critically impact their efficacy. In this review, we summarize the underappreciated roles that fucosylation plays in cancer and immune cells, as well as the fucosylation of therapeutic antibodies or the manipulation of fucosylation and their implications as new therapeutic modalities for cancer.