ABCB1 and neoplasm: Our analysis of the selected polymorphisms in the MDR-1 gene, whose results are reported in Table 1, revealed that in two of the tested cell lines (non-tumor H6c7 and PANC-1), polymorphisms in exons 12 (1236T>C) and in exon 21 (2677T>G) are present in heterozygosis.