Pathways connecting inflammation and cancer.

Area of Science:

• Oncology
• Immunology
• Pathogenesis

Background:

• Chronic inflammation is a significant risk factor for cancer development and carcinogenesis.
• Inflammation is present in the tumor microenvironment of most cancers, including those not epidemiologically linked to infectious agents.
• Key components of cancer-associated inflammation include infiltrating leukocytes, cytokines, chemokines, growth factors, lipid mediators, and matrix-degrading enzymes.

Purpose of the Study:

• To elucidate the intricate relationship between inflammation and cancer development.
• To describe the molecular and cellular mechanisms linking inflammation to carcinogenesis.
• To highlight the dual role of intrinsic and extrinsic pathways in mediating inflammation's contribution to tumor progression.

Main Methods:

• Review and synthesis of existing literature on inflammation and cancer.
• Analysis of the molecular hallmarks of cancer-associated inflammation.
• Examination of the interplay between genetic events, tumor microenvironment, and infiltrating leukocytes.

Main Results:

• Inflammation is a critical factor in carcinogenesis, implicated in 15-20% of human tumors via infection-driven pathways.
• Tumor microenvironments consistently exhibit inflammatory components, regardless of direct pathogen association.
• Two primary pathways, intrinsic (tumor cell-driven) and extrinsic (leukocyte-driven), interconnect inflammation and cancer progression.

Conclusions:

• Persistent inflammation is a fundamental contributor to cancer initiation and progression.
• Tumor-infiltrating leukocytes, particularly macrophages, are central regulators of the inflammatory tumor microenvironment.
• Understanding these inflammation-cancer pathways is crucial for developing novel therapeutic strategies.