Moreover, in accordance with our previous study demonstrating that chromosomal aneuploidy in CTCs correlates to either intrinsic or the acquired cisplatin resistance in gastric cancer patients [16], different subtypes of CTC classified upon their chromosome 8 ploidy and CK18 expression examined by CK-i•FISH® were found to have distinct diverse sensitivities to cisplatin in GA0087 PDX mice. The gene discussed is CHKA; the disease is gastric cancer.