When the cancer disease is represented by a plant, the cancerous cells can be seen as the ‘seeds’, and the surrounding tissue (also called micro-environment or terrain) as the ‘soil’. Conventional cancer therapies are preoccupied with removing the ‘seeds’, while the integrative approach to cancer looks after the ‘seed and soil’. Real success in cancer treatment can only be achieved with a combined approach, namely removing all seeds, and healing the soil at the same time.
The “seed and soil” hypothesis, referred to in the metaphor, was first published by Stephen Paget in 1889 and still is recognized and widely accepted today. Since more than a century, we know that certain tumors exhibit a predilection for metastases to specific organs. This organ-preference pattern of tumor metastases formation is the result of highly specific interactions between metastatic tumor cells (the seeds) and the tissue microenvironment or terrain, in which cancer grows (the soil).
During the last century, we have observed an explosion in our cancer knowledge base, including the latest technological progress in gene sequencing and molecular profiling. An extensive collection of experimental research and clinical data is now revealing valuable details about the interactions between cancer cells and their microenvironment, consisting of stromal cells and the extracellular matrix. We know today that the fate of a metastatic cancer cell depends on its ability to trigger various homeostatic mechanisms in this tissue microenvironment, thereby promoting cell growth, cell survival, invasion of microenvironment, angiogenesis, and clonal expansion to form a metastasis.
Understanding those interactions will help us to target important molecules and/or pathways in the crosstalk between cancer cells and their microenvironment and hopefully lead to better strategies for prevention and treatment of metastatic disease which remains the major cause of cancer-related death today.