Researchers have revealed that not all malignant cells in tumors divide continuously, as a percentage of them enter a dormant state, averaging 7.2%.
This was demonstrated in a study published in the journal Genome Medicine, which showed that these cells are particularly dangerous because they are able to survive chemotherapy, then reactivate themselves and trigger tumor growth again, according to oncologist Alexis Parr of Imperial College London.
Furthermore, these cells are inherently resistant to treatment from the outset, even before treatment begins. These dormant cells are often surrounded by macrophages that produce the CXCL10 protein, as well as fibroblasts, which are connective tissue cells that contribute to tumor support. This "envelope" can prevent drugs and immune cells from reaching their target cells.
Study participant Maria Secreir from University College London said: "We don't yet know who is driving this process: the tumor or its guardians? It is likely that the relationship between them goes both ways."
The study authors believe that future treatments should target both active areas where cells are dividing and inactive areas within the tumor.
Despite the danger of dormant cells, their presence may in some cases be a positive predictive indicator, as statistical analysis has shown that a high percentage of them in hormone-positive tumors is associated with a longer period of survival without relapse.
