ABCB1 and neoplasm: In general, our study observed increased mRNA expression of MDR1 in both heterozygous and homozygous mutations in exons 12 and 26 in majority of the resistant samples as shown in Table 6, and thus we can suggest that chemotherapeutic resistant development in tumor samples seem to be appeared not only due to combinatorial effect of more than one mutation but also the stage of tumor plays a significant role in conferring resistance phenotype in OC patients.