title: bcl-2 expression is reciprocal to p53 and c-myc expression in metastatic human colorectal cancer.
abstract: Apoptosis (programmed cell death) inhibition may be an important mechanism by which gastrointestinal mucosal cells containing damaged DNA evade normal clearance mechanisms and grow to become invasive tumours. Since bcl-2 is an apoptosis inhibitor, bcl-2 mRNA expression was measured in 21 metastases of colorectal cancer using reverse transcription-polymerase chain reaction analysis. The mean bcl-2 mRNA expression (0.45 U, P < 0.0001) was lower than that of normal mucosal controls (= 1 U). p53 expression was inversely correlated with bcl-2 expression (P = 0.021) in 19 evaluable samples, and in tumours where p53 expression was over twice that of normal colonic mucosal values, bcl-2 mRNA was significantly decreased (mean 0.30, P = 0.0052). c-myc was also inversely correlated with bcl-2 expression (P = 0.025). Decreased bcl-2 expression in metastatic colorectal cancer may be partly due to allelic loss, given the proximity of bcl-2 to the frequently deleted DCC gene on chromosome 18q. However, the inverse correlation to p53/c-myc suggests an active downregulation of bcl-2, possibly following delegation of its apoptosis inhibiting role to other genes.
authors.affiliation: Division of Oncology, Kantonsspital Basle, Switzerland.
authors.forename: R A
authors.initials: RA
authors.lastname: Popescu
authors.forename: A
authors.initials: A
authors.lastname: Lohri
authors.forename: E
authors.initials: E
authors.lastname: de Kant
authors.forename: C
authors.initials: C
authors.lastname: Thiede
authors.forename: J
authors.initials: J
authors.lastname: Reuter
authors.forename: R
authors.initials: R
authors.lastname: Herrmann
authors.forename: C F
authors.initials: CF
authors.lastname: Rochlitz
mesh_terms: D017209:Apoptosis / Q000235:genetics; D002851:Chromatography, High Pressure Liquid; D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D015870:Gene Expression; D011905:Genes, ras; D006801:Humans; D009154:Mutation; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D019253:Proto-Oncogene Proteins c-bcl-2; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D016159:Tumor Suppressor Protein p53