Oncologists have long puzzled over the fact that after cancer treatment, single cancer cells that are dispersed throughout the body – so-called disseminated tumor cells – are quick to grow and form secondary tumors called metastases in certain organs, while in other organs they metastasize more slowly, sometimes decades later. Such is the case with head and neck squamous cell carcinoma (HNSCC) cells, which remain dormant when lodged in bone marrow but rapidly form tumors when they make their way into the lungs.
A study published online October 27 by Nature Cell Biology by Bragado et al. reveals that bone marrow contains high levels of TGFβ2, which activates the tumor suppressor gene p38 in tumor cells and triggers a cascade of events that renders tumor cells dormant and keeps HNSCC growth in check. In the lungs, where TGFβ2 is in short supply, these cells rapidly form tumors.
The research team, led by Julio A. Aguirre-Ghiso, PhD, Associate Professor of Medicine, Hematology and Medical Oncology, and Otolaryngology at the Icahn School of Medicine at Mount Sinai, is the first to identify the role of TGFβ2 in determining whether HNSCC cells will remain harmlessly dormant or behave aggressively in a given location. The study confirms a century-old theory called the “seed and soil” theory of metastasis, which suggests that a tumor cell – the seed – either sleeps or thrives within the unique environment of each organ – the soil.
Read more at: MedicalXpress