title: Unfavourable expression of pharmacologic markers in mucinous colorectal cancer.
abstract: Patients with mucinous colorectal cancer generally have worse prognoses than those with the nonmucinous variety. The reason for this disparity is unclear, but may result from a differential response to adjuvant chemotherapy. We examined known molecular markers for response to common chemotherapy in these two histological subtypes. In all, 21 patients with mucinous and 30 with nonmucinous Dukes C colorectal cancer were reviewed for demographic data and outcome. Total RNA from the tumours and adjacent normal mucosa was isolated and reverse transcribed. Quantitative expression levels of drug pathway genes were determined using TaqMan RT-PCR (5-fluorouracil (5-FU): TYMS, DPYD, ECGF1; oxaliplatin: GSTP1 (glutathione S-transferase pi), ERCC1 and 2; irinotecan: ABCB1, ABCG2, CYP3A4, UGT1A1, CES2, TOP1). Mucinous tumours significantly overexpressed both TYMS and GSTP1 relative to nonmucinous tumours and patient-matched normal mucosa. No significant differences in expression of the remaining markers were found. Mean follow-up was 20 months; 17 patients had recurrent disease. Among patients receiving 5-FU, those with mucinous tumours experienced shorter disease-free survival (DFS) than those with nonmucinous tumours (median DFS 13.8 vs 46.5 months, P=0.053). Mucinous colorectal cancer overexpresses markers of resistance to 5-FU and oxaliplatin. Likewise, DFS may be decreased in patients with mucinous tumours who receive 5-FU. The presence of mucin should be carefully evaluated in developmental trials of new agents for treating colorectal cancer.
authors.affiliation: Department of Surgery, Washington University School of Medicine, St Louis, MI, USA. hmcleod@im.wustl.edu
authors.forename: S C
authors.initials: SC
authors.lastname: Glasgow
authors.forename: J
authors.initials: J
authors.lastname: Yu
authors.forename: L P
authors.initials: LP
authors.lastname: Carvalho
authors.forename: W D
authors.initials: WD
authors.lastname: Shannon
authors.forename: J W
authors.initials: JW
authors.lastname: Fleshman
authors.forename: H L
authors.initials: HL
authors.lastname: McLeod
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000494:pharmacology; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D017931:DNA Primers; D018572:Disease-Free Survival; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D005260:Female; D005472:Fluorouracil / Q000494:pharmacology; D006801:Humans; D000077146:Irinotecan; D008297:Male; D009944:Organoplatinum Compounds / Q000494:pharmacology; D000077150:Oxaliplatin; D011379:Prognosis; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D014408:Biomarkers, Tumor; D017931:DNA Primers; D009944:Organoplatinum Compounds; D012333:RNA, Messenger; D000077150:Oxaliplatin; D000077146:Irinotecan; D005472:Fluorouracil; D002166:Camptothecin