title: Intrinsic variability in the detection of micrometastases in lymph nodes for re-staging of colorectal cancer. effect of individual markers and tissue samples.
abstract: In this study, we investigated whether (a) carcinoembryonic antigen (CEA), cytokeratin-20 (CK-20) and guanylyl cyclase C (GCC) are clinically useful markers for the molecular detection of submicroscopic metastases in colorectal cancer (CRC) and (b) whether overexpression of CEA, CK-20 and GCC can be reliably detected in formalin-fixed, paraffin-embedded tissues as well as frozen lymph nodes. We studied 175 frozen lymph nodes and 158 formalin-fixed, paraffin-embedded lymph nodes from 28 cases of CRC. CEA or CK-20 or GCC-specific polymerase chain reaction (PCR) was carried out on mRNA transcripts extracted from the nodal tissues. Ten out of 11 Dukes' B CRC cases had detectable CEA and CK-20 while 6 out of 11 Dukes' B CRC cases had detectable GCC. In general, the difference of re-staged cases when comparing frozen and paraffin-embedded samples was marked; the only statistically significant correlation between frozen and paraffin tissue was for the CEA marker. Our results indicated a high incidence (>50%) of detecting micrometastases in histologically-negative lymph nodes at the molecular level.
authors.affiliation: Department of Pathology, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore.
authors.forename: M
authors.initials: M
authors.lastname: Salto-Tellez
authors.forename: S L
authors.initials: SL
authors.lastname: Kong
authors.forename: A P K
authors.initials: AP
authors.lastname: Leong
authors.forename: E S C
authors.initials: ES
authors.lastname: Koay
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D002272:Carcinoembryonic Antigen / Q000032:analysis; D015179:Colorectal Neoplasms / Q000737:chemistry* / Q000473:pathology*; D005260:Female; D006162:Guanylate Cyclase / Q000032:analysis; D006801:Humans; D007381:Intermediate Filament Proteins / Q000032:analysis; D053554:Keratin-20; D008207:Lymphatic Metastasis / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014407:Tumor Cells, Cultured
chemical_list: D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D007381:Intermediate Filament Proteins; C507499:KRT20 protein, human; D053554:Keratin-20; D006162:Guanylate Cyclase