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Copyright ©2014 Baishideng Publishing Group Inc.
World J Gastroenterol. Nov 7, 2014; 20(41): 15049-15059
Published online Nov 7, 2014. doi: 10.3748/wjg.v20.i41.15049
Table 1 Synopsis of major biomarkers derived from clinical studies for use with epidermal growth-factor receptor-targeted therapies in colorectal cancer, chemotherapy
BiomarkersPrognosticPredictivePredictive efficacyMethodology usedClinical status
EGFR copy number[71]YesYesRaised EGFR GCN and chromosome 7 polysomy associated with response rate (RR) of 30% vs 0% (PAN)Fluorescence in situ hybridizationAwaiting further clinical validation
EGFR ligand expression (epiregulin and amphiregulin)[72,73]YesYesHigher gene-expression profile of ligands in patients with disease control compared to non-responders to CET; OR for response 1.90 for epiregulin and 1.86 for amphiregulinGene-expression profiles using RNA and FFPE tumorsAwaiting further clinical validation
Activating KRAS mutations in codon 12 and 13[48,74]YesPredictive for lack of responseRR of 12%-17% for KRAS WT patients vs 0%-1% for KRAS mutations (PAN and CET)PCR on DNA extracted from FFPE samplesFDA-approved clinical biomarker
KRAS G13D mutations[59,75]YesPredictive for lack of responseNo difference in response rates between G13D and activating KRAS mutations but, 3.6- and 2.1-mo improvement in OS and PFS[75] ,improved RR, OR 3.38, 40.5% vs 22%[59] (CET + chemo)PCR on DNA extracted from FFPE samples from multiple studiesSmall patient numbers; awaiting results of prospective study (ICECREAM)
NRAS and BRAF mutations[49,76-78]YesPredictive for lack of responseLower RR for NRAS and BRAF mutations vs WT (7.7% and 0%-8.3% vs 38% and 17%-47%, respectively) (all KRAS WT patients treated with CET and PAN)Mutation-frequency analysis using PCR and mass spectrometry (FFPE and fresh-frozen samples)Evidence for significant negative association, but further clinical validation required
PIK3CA exon 20 mutations[77]NoPredictive for lack of response0% vs 36.8% RR for exon 20 mutations vs WTMutation-frequency analysis using PCR and mass spectrometry (FFPE and fresh-frozen samples)Conflicting evidence when compared to other studies, further validation required
Serpin B5YesNoNoHEAwaiting further clinical validation
Mucinous histologyYesYesNoHEConfirmed data
Table 2 Synopsis of major prognostic clinical factors derived from clinical studies on colorectal cancer, chemotherapy
Prognostic clinical factorsPositiveNegativeMethodology usedPredictive of response to therapy
Age:CE
YoungNoYesNo
Elderly (according to CGA):Some limitations to choose the T
FitYesNo
UnfitNoYes
FrailNoYes
PS-WHO:CENo
≤ 1YesNo
≥ 2NoYes
HIV+NoYesLT, CEPoor
Advanced clinical stateNoYesTNM, CENo
Elevated CEA levels:LTNo
AdjuvantNoYes
MetastaticNoYes
Elevated Ca19.9 levelsNoYesLTNo
Elevated ALP levelsNoYesLTPoor
Skin rash[79,80]YesYesHEFurther clinical validation required
Hypomagnesaemia[81,82]Conflicting evidenceConflicting evidencePlasma magnesium levelsFurther clinical validation required
Co-morbiditiesNoYesACE-27[83]/CESome limitation to choose the T