title: Adequacy of colonoscopic biopsy specimens for molecular analysis: a comparative study with colectomy tissue.
abstract: Molecular analyses of tumors are increasingly useful for prognosis and for guiding therapy. Colonoscopic biopsy provides the first source of tissue for most cases of colorectal carcinoma and therefore might become an important source for molecular analyses. We have addressed the question whether molecular analyses of colonoscopic biopsy yield results similar to the findings from the surgical specimen. Further, we analyzed 2 separate areas of the colectomy specimen to assess tumor heterogeneity. We evaluated 3 samples from each of 67 patients for point mutations in the KRAS gene, loss of heterozygosity (LOH) at the Adenomatous Polyposis Coli (APC) and Deleted in Colon Cancer (DCC) genes and for microsatellite instability (MSI) using polymerase chain reaction based techniques. The average time interval between biopsy and surgery was 2.2+/-0.15 weeks. Lesions were from all colon segments and all surgical stages. The degree of agreement between the biopsy and surgical sites was high for APC LOH, MSI, and KRAS mutations (kappa=0.85, 1.00, and 0.93, respectively) but less so for DCC LOH (kappa=0.62). Colonoscopic biopsies are an acceptable source of neoplastic DNA for studies of KRAS, APC LOH, and MSI, but less so for DCC LOH, primarily resulting from technical considerations.
authors.affiliation: Department of Medicine, Saint Barnabas Medical Center, Livingston, NJ 07039, USA. pzauber@aol.com
authors.forename: Neil P
authors.initials: NP
authors.lastname: Zauber
authors.forename: Marlene
authors.initials: M
authors.lastname: Sabbath-Solitare
authors.forename: Stephen
authors.initials: S
authors.lastname: Marotta
authors.forename: Lilani P
authors.initials: LP
authors.lastname: Perera
authors.forename: David T
authors.initials: DT
authors.lastname: Bishop
mesh_terms: D001706:Biopsy; D003082:Colectomy; D003106:Colon / Q000473:pathology*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D004273:DNA, Neoplasm / Q000032:analysis*; D017491:Genes, APC; D016163:Genes, DCC; D042822:Genomic Instability; D006801:Humans; D019656:Loss of Heterozygosity; D018895:Microsatellite Repeats; D017354:Point Mutation; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins
chemical_list: D004273:DNA, Neoplasm; C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins