Organotropisme

Organotropisme, or organotropism in English, is the tendency of cancer cells to metastasize preferentially to certain organs rather than to random sites. It reflects a combination of tumor cell properties and the microenvironment of distant tissues, and it is a central concept in understanding metastatic spread rather than primary tumor growth. The idea is historically linked to the seed and soil hypothesis, which posits that disseminated tumor cells (the seeds) thrive only in compatible organ environments (the soils).

Several mechanisms contribute to organotropisme. Hemodynamic patterns influence where circulating tumor cells lodge. Adhesion molecules, proteases, and the ability to invade endothelium affect extravasation into target tissues. Chemokine signaling, such as CXCR4 binding CXCL12, can guide tumor cells toward organs rich in the ligand. Tumor-derived exosomes may precondition distant sites by shaping the stroma and recruiting bone marrow–derived cells, creating pre-metastatic niches. The intrinsic traits of tumor cells and the resident organ microenvironment, including immune components, stromal cells, and metabolic conditions, determine the likelihood of successful colonization.

Examples of organotropism are common in clinical cancer care: breast cancer often metastasizes to bone, liver, lung, and brain; prostate cancer frequently to bone; colorectal cancer to the liver; and melanoma to brain and other tissues. Organotropism varies among tumor subtypes and individual patients, affecting prognosis and treatment planning.

Understanding organotropisme informs research into preventing or treating metastasis by targeting chemokine axes, niche formation, and organ-specific interactions.