ABCG2 and colonic neoplasm: Using mRNA expression data from patients enrolled in the PETACC-3 study [12], it appeared that in the adjuvant setting of stage III colon cancer increased ABCG2 mRNA expression together with low Topoisomerase 1 (TOP 1) gene expression were associated with decreased benefit from the addition of irinotecan to 5-FU [13].