Colorectal precancers: a review describes the dual role of immunity

A review focused on precancerous lesions

Colorectal cancer develops mainly through a sequence from adenoma to carcinoma. The review examines the role of immune processes in this progression, whose mechanisms remain incompletely understood.

The authors searched MEDLINE, Embase and the Cochrane Library for studies published between October 1974 and July 2021. The selected studies examined immune cell infiltration, cytokine profiles and immune surveillance in colorectal precancers.

Only the PubMed abstract is available in the source material. It specifies neither the number of studies included, nor the total sample size, nor their detailed characteristics. It therefore does not allow a direct assessment of the strength of each finding.

An immune response that works both ways

According to this review, the presence of adaptive immune cells changes across the stages of the adenoma–carcinoma sequence. Some lymphocyte subsets contribute to immunosuppression that favors tumor progression, while others play a protective role.

Innate immune cells also have context-dependent roles. Cytokine networks, including IL-6, IL-8 and IL-17, help modulate the tumor microenvironment.

The important distinction is this: increased immune activity is not, on its own, a sign of protection. The cell types involved and the biological context matter. The abstract describes complex, nonlinear relationships, not a single mechanism to stimulate.

Research avenues, not proven prevention

The authors present these mechanisms as a basis for developing approaches to prevention, early detection and intervention that take immunity into account. However, the abstract reports no quantified clinical benefit from such an approach.

This review therefore does not support recommending any food, supplement or intervention intended to modify these immune responses. It identifies biological avenues for research without demonstrating that manipulating them would reduce colorectal cancer risk.

What we can take away

Immunity can protect tissues or accompany the progression of colorectal precancers. This review helps explain this dual role without providing any new validated preventive measure.