Tumor-associated macrophages (TAMs) as biomarkers for gastric cancer: A review

Gastric adenocarcinoma is one of the most common types of cancer worldwide, with an incidence of a million new cases annually. In addition to having a high mortality rate due to often delayed detection and its poor response to cancer therapy, it also spreads aggressively. Inflammation has been shown to play a role in carcinogenesis. Consequently, macrophages are important in phagocytosis, antigen presenting and producing cytokines and growth factors. As a response to microenvironmental signals, they may polarize into tumor resisting M1 or tumor promoting M2 macrophages. Recently, studies have indicated that M2-type macrophage resembling tumor-associated macrophages (TAMs) might be used as an independent prognostic factor for gastric cancer. This review will discuss the possible use of TAMs as prognostic tools for gastric cancer and whether they are suitable for use in clinical environment.