Metabolic Microenvironment: Gastric Cancer

Malignancy may be characterized as a state formed in the setting of specific tumor–host relationships
at the molecular and cellular microenvironment levels. R.E. Kavetsky and his collaborators distinctly
outlined the concept of “tumor–host” interaction. Tumor is a complicated biological system closely
connected with the organism, where it initiated and develops. Tumor cells are in environment of
different factors that form tumor microenvironment that plays an active role in disease progression.
There are two types of tumor microenvironment: the metabolic microenvironment mediated by factors
of tumor microphysiology (blood flow, vascular permeability, oxygenation, extracellular рН, interstitial
fluid pressure, etc.), and the cellular-molecular microenvironment comprising interactions between
tumor cells and non-tumor cells and the factors of the stromal compartment. Factors of tumor
microphysiology can modify the interaction between tumor cells and surrounding non-tumor cells and
molecular components and moreover they form the tumor profile that influence the pressure of tumor
on the host. The review presents the data concerning the role of metabolic microenvironment of tumor
cells from the point of “tumor-host” interaction in order to employ these parameters to working out the
methods of diagnosis and prognosis of disease outcome of patients with gastric cancer. Special
attention has been paid to hypoxia as a key factor of metabolic microenvironment that positively
affects tumor progression, stimulating its aggressiveness, metastasis and resistance to therapy and is
regarded as a factor of unfavorable prognosis. It was shown that there is possible clinical relevance of
tumor classification based on the level of tumor oxygenation that may be advantageous for selection
of patients for individualized therapy that may give the hope for enhancement of treatment efficacy.