Clinically applicable pharmacogenomics of anti-cancer drugs

In addition to drug metabolizing enzymes, drug transporters play an important role in pharmacodynamic (PD) and pharmacokinetic (PK) outcomes in anti-cancer drug therapy. Among the various drug transporters, ABC transporters such as MDR1, MRP1, MRP2 and BCRP are well known multiple anti-cancer drug resistance proteins. Individualized anti-cancer drug therapy based on the expression levels of these ABC transporters in cancer tissues has already been applied in the surgical treatment of glioblastoma and anaplastic astrocymota. OATP1B1 (organic anion transporting polypeptide 1B1), an influx transporter expressed at the basolateral membranes of hepatocytes, is also involved in the PK profile of irinotecan. Recent studies suggest that the screening of UGT1A1 variants (e.g., *28 and *60) and SLCO1B1 variants (especially for *15) is useful in irinotecan chemotherapy to avoid unpredicted severe toxicity.