Indeed, one of the anticipated clinical significance of CTC subtypes has been confirmed in our recent studies performed on the advanced gastric cancer patients, showing that among CK18 negative CTCs, trisomy in chromosome 8 CTC may possess intrinsic resistance to the chemotherapeutic drug cisplatin, compared to the tetra- and/or pentasomy subtype which developed the acquired cisplatin resistance [30]. The gene discussed is KRT18; the disease is gastric cancer.