title: p53 genetic alterations, protein expression and autoantibodies in human colorectal carcinoma: A comparative study.
abstract: This study investigated a total number of 120 colorectal malignant tumor tissues by applying a new quantitative luminometric assay (LIA)-mat, immunohistochemistry (IHC) (n=100), PCR/SSCP (n=42), and sequencing (n=7). Sera were collected from 235 patients suffering from colorectal carcinoma in addition to 195 healthy individuals as a control group. Manual ELISA kit was developed to detect p53 autoantibodies in the sera of those patients. Our data demonstrated that the LIA-mat yields reliable estimates of p53 expression in soluble cell extracts as compared with results obtained by immunohistochemistry which showed positive immunostaining in 63% of the studied cases. Using a cut-off value of 1.8 ng/mg protein, 65 tumors out of 120 (54%) were classified to be positive by LIA-mat, manifesting protein overexpression, while 22 out of 42 (52%) tumor samples showed p53 gene alteration when applying single strand conformation polymorphism (SSCP) analysis on polymerase chain reaction products. In tumor samples without a p53 gene alteration, the median soluble p53 protein level was 4.3 ng/mg protein, whereas the median p53 protein level for tumor samples with p53 gene alteration was 7.5 times higher. Despite a significant correlation between the outcome of LIA and SSCP, a disagreement was found in 30% of cases. We found no significant correlation between p53 protein overexpression and clinicopathological findings except for distant metastasis (p=0.33), indicating p53 immunoreactivity to be an independent prognostic factor. Our data showed that 18% of patients suffering from colorectal cancer developed autoantibodies against p53 in their sera which might be an early indicator for tumor development and distant metastasis.
authors.affiliation: Department of Clinical Biochemistry, University of Damascus Syria.
authors.forename: R
authors.initials: R
authors.lastname: Hallak
authors.forename: J
authors.initials: J
authors.lastname: Mueller
authors.forename: O
authors.initials: O
authors.lastname: Lotter
authors.forename: S
authors.initials: S
authors.lastname: Gansauge
authors.forename: F
authors.initials: F
authors.lastname: Gansauge
authors.forename: M
authors.initials: M
authors.lastname: el-Deen Jumma
authors.forename: M
authors.initials: M
authors.lastname: Montenarh
authors.forename: F
authors.initials: F
authors.lastname: Safi
authors.forename: H
authors.initials: H
authors.lastname: Beger
mesh_terms: D001323:Autoantibodies / Q000097:blood*; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism; D005091:Exons; D016158:Genes, p53; D006801:Humans; D007150:Immunohistochemistry; D009154:Mutation; D016133:Polymerase Chain Reaction; D011379:Prognosis; D016159:Tumor Suppressor Protein p53 / Q000032:analysis* / Q000276:immunology
chemical_list: D001323:Autoantibodies; D016159:Tumor Suppressor Protein p53