Irinotecan-induced diarrhea: functional significance of the polymorphic ABCC2 transporter protein

Clin Pharmacol Ther. 2007 Jan;81(1):42-9. doi: 10.1038/sj.clpt.6100019.


Interindividual pharmacokinetic variability of the anticancer agent irinotecan is high. Life-threatening diarrhea is observed in up to 25% of patients receiving irinotecan and has been related with irinotecan pharmacokinetics and UGT1A1 genotype status. Here, we explore the association of ABCC2 (MRP2) polymorphisms and haplotypes with irinotecan disposition and diarrhea. A cohort of 167 Caucasian cancer patients who were previously assessed for irinotecan pharmacokinetics (90-min infusion given every 21 days), toxicity, and UGT1A1*28 genotype were genotyped for polymorphisms in ABCC2 using Pyrosequencing. Fifteen ABCC2 haplotypes were identified in the studied patients. The haplotype ABCC2*2 was associated with lower irinotecan clearance (28.3 versus 31.6 l/h; P=0.020). In patients who did not carry a UGT1A1*28 allele, a significant reduction of severe diarrhea was noted in patients with the ABCC2*2 haplotype (10 versus 44%; odds ratio, 0.15; 95% confidence interval, 0.04-0.61; P=0.005). This effect was not observed in patients with at least one UGT1A1*28 allele (32 versus 20%; odds ratio, 1.87; 95% confidence interval, 0.49-7.05; P=0.354). This study suggests that the presence of the ABCC2*2 haplotype is associated with less irinotecan-related diarrhea, maybe as a consequence of reduced hepatobiliary secretion of irinotecan. As the association was seen in patients not genetically predisposed at risk for diarrhea due to UGT1A1*28, confirmatory studies of the relationships of ABCC2 genotypes and irinotecan disposition and toxicity are warranted.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Aged
  • Alleles
  • Antineoplastic Agents, Phytogenic / adverse effects*
  • Antineoplastic Agents, Phytogenic / pharmacokinetics*
  • Antineoplastic Agents, Phytogenic / pharmacology
  • Camptothecin / adverse effects
  • Camptothecin / analogs & derivatives*
  • Camptothecin / pharmacokinetics
  • Camptothecin / pharmacology
  • Diarrhea / chemically induced*
  • Female
  • Glucuronosyltransferase / genetics
  • Humans
  • Irinotecan
  • Male
  • Membrane Transport Proteins / genetics*
  • Middle Aged
  • Multidrug Resistance-Associated Proteins / genetics*
  • Polymorphism, Single Nucleotide


  • Antineoplastic Agents, Phytogenic
  • Membrane Transport Proteins
  • Multidrug Resistance-Associated Proteins
  • multidrug resistance-associated protein 2
  • Irinotecan
  • UGT1A1 enzyme
  • Glucuronosyltransferase
  • Camptothecin