Cancer-Associated Myeloid Regulatory Cells

Area of Science:

• Oncology
• Immunology
• Cell Biology

Background:

• Myeloid cells are crucial in cancer development and therapy resistance within the tumor microenvironment (TME).
• Current classification using cell markers is challenging due to overlapping features and plasticity.
• Existing paradigms like type 1/type 2 activation do not fully capture myeloid cell roles in cancer progression or rejection.

Purpose of the Study:

• To challenge the exclusive reliance on cell markers for identifying myeloid cell subsets in the TME.
• To propose a new functional classification of myeloid cells as either regulatory or stimulatory.
• To emphasize targeting protumor traits for enhanced cancer immunotherapy.

Main Methods:

• Review and critical analysis of existing literature on myeloid cell biology in cancer.
• Conceptual framework development for functional classification of myeloid cells.
• Discussion of therapeutic implications based on functional categorization.

Main Results:

• Cell markers are insufficient for unambiguous identification of myeloid cell subsets in the TME.
• Myeloid cells exhibit plasticity and shared functional/metabolic characteristics, complicating subset-based analysis.
• A functional classification into myeloid regulatory cells (promoting tumor progression) and myeloid stimulatory cells (promoting tumor rejection) is proposed.

Conclusions:

• Rethinking myeloid cell classification from subset-based to function-based is essential for therapeutic advancement.
• Targeting protumor traits of myeloid cells, rather than specific subsets, holds greater promise for effective cancer immunotherapy.
• This functional approach aims to significantly improve the efficacy of antitumor immunotherapies.