question: How rare are CTCs (circulating tumour cells) in the plasma of patients?
answer: Circulating tumour cells (CTCs) are significantly rare entity in the blood of patients with non-small cell lung cancer (NSCLC) patients as well as in other types of cancer. Small-cell lung cancer cells are typically quiescent, whereas CTCs can be up-regulated in response to radiation or chemical agents and may contribute to tumorigenesis as an endogenous red cell marker.