Moreover, exosomes contribute to tumor chemotherapy resistance by facilitating the activity of efflux pump transporters such as P-glycoprotein(P-gp), multidrug resistance protein-1 (MRP-1), ATP-binding cassette transporter A3 (ABCA-3), and ATP-binding cassette transporter G2 (ABCG-2) (Shedden et al., 2003; Levchenko et al., 2005; Ambudkar et al., 2005). Here, ABCG2 is linked to neoplasm.