New foods and natural biological modulators have recently become of scientific interest in the investigation of the value of traditional medical therapeutics. Glucans have an important part in this renewed interest. These fungal wall components are claimed to be useful for various medical purposes and they are obtained from medicinal mushrooms commonly used in traditional Oriental medicine. The immunotherapeutic properties of fungi extracts have been reported, including the enhancement of anticancer immunity responses. These properties are principally related to the stimulation of cells of the innate immune system. The discovery of specific receptors for glucans on dendritic cells (dectin-1), as well as interactions with other receptors, mainly expressed by innate immune cells (e.g., Toll-like receptors, complement receptor-3), have raised new attention toward these products as suitable therapeutic agents. We briefly review the characteristics of the glucans from mycelial walls as modulators of the immunity and their possible use as antitumor treatments.

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The mammalian microbiota plays a crucial role in the pathogenesis of many diseases. Thanks to recent advances in metagenomics, proteomics, and metabolomics, microbiome composition and metabolic activity can now be studied in detail. Results obtained by such fascinating and provocative studies would be meaningless without considering the perspective of the whole organism. Our work using gnotobiology as the major tool to unravel the mechanisms of host-microbe interaction has demonstrated the crucial role of microbiota in the initiation and progression of inflammation-associated colorectal neoplasia. Carcinogenesis in the gut is driven by the presence of potentially harmful microbes or by lack of protective ones, by the production of carcinogens generated by microbes, and by the induction of inflammation and modulation of the immune system. Here, we review these mechanisms with special emphasis on those where gnotobiology has yielded important insights.