[Relationship between expression of c-myc and p53 in liposarcoma].
OBJECTIVE
The relationship between liposarcoma and gene c-myc and p53 is not clear. There are also different reports on p53 mutation in liposarcoma. This study was designed to investigate the relationship between the expression of c-myc and p53 genes and liopsarcomas. We hope to better understand the role of the c-myc and p53 genes in molecular biology.


METHODS
Immunohistochemical labelled streptavidin-biotin (LSAB) method, single strand conformation polymorphism analysis of polymerase chain reaction products (PCR-SSCP), and DNA sequencing were used.


RESULTS
38.09% (16/42) liposarcoma samples detected were immunohistochemically c-myc protein positive. p53 protein was detected in 52 liposarcomas with the positive staining rate of 48.08% (25/52). In different subtypes of liposarcomas, the positive staining rates of c-myc and p53 gene proteins were much lower in well-differentiated liposarcomas than in the poorly differentiated liposarcomas. There was a positive correlation between c-myc and p53 expression in liposarcoma. There was no statistical significance for the different positive staining rate of c-myc and p53 protein in the primary and the recurrent liposarcoma. Abnomality in the single-stranded DNA pattern was determined by PCR-SSCP analysis in 2 samples (pleomophic liposarcomas). Missense mutation in exon 8 of codon 268 of p53 gene (AAC-->ATC) were detected by DNA sequencing. Another heterozygotic cosense mutation may exist at exon 6 of codon 221 of p53 gene (GAG-->GAA).


CONCLUSIONS
The c-myc and p53 protein are associated with the development, differentiation, and malignancy of liposarcoma, but not with the recurrence of liposarcoma. Detecting the level of c-myc and p53 protein expression may be valuable in evaluating the level of differentiation and malignancy of liposarcoma. c-myc and p53 play synergic roles in the cooperation of development of liposarcoma. There appear the point mutation on exon 8, 6 of p53 gene.
Wang
Ya-lan
YL
Department of Pathology, Chongqing University of Medical Sciences, Chongqing 400016, P. R. China.
Qiu
Ju-shi
JS
Xiong
Ming
M
D004247:DNA / Q000737:chemistry; D016158:Genes, p53; D006801:Humans; D007150:Immunohistochemistry; D008080:Liposarcoma / Q000737:chemistry* / Q000235:genetics / Q000473:pathology; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D016271:Proto-Oncogene Proteins c-myc / Q000032:analysis*; D016159:Tumor Suppressor Protein p53 / Q000032:analysis*
D016271:Proto-Oncogene Proteins c-myc; D016159:Tumor Suppressor Protein p53; D004247:DNA