Exon significance

Ameyaw MM, Regateiro F, Li T, Liu X, Tariq M, Mobarek A et al. MDR1 pharmacogenetics frequency of the C3435T mutation in exon 26 is significantly influenced by ethnicity. Pharmacogenetics 2001 11(3) 217—221. 

P-gp polymorphisms are also reported to affect the outcome of therapy in patients with AML. Ulmer et al. (69) compared the clinical course of AML treatment with the anticancer drugs etoposide, mitoxantrone, or daunorubicin among patients with various P-gp genotypes and demonstrated that patients homozygous for the wild-type allele at any locus investigated (exons 12,21, and 26, respectively, for P-gp 8, 7, and 6) exhibited a significantly decreased overall survival with a higher probability of relapse. Theoretically, a reduced intracellular concentration of... 

As for the Block C (exons 2-5) haplotype IB, its significant associations with reduced AUC ratios and neutropenia were not clearly demonstrated, but a possible contribution under co-occurrence with haplotype 60 was suggested (38,47). In fact, the combinatorial haplotype 60 - IB increased bilirubin levels in healthy Japanese subjects (50). Because the frequency of IB homozygotes is rather low in Asians (39), further studies in other ethnic populations would clarify the role of 60- IB in irinotecan treatment. 

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